Tom is sitting in a hotel lobby, facing the reception desk, and observing customers checking into their rooms. He is playing a game with himself where he tries to guess whether each customer is visiting on vacation, or on business. On one occasion, he sees a new customer, in neutral clothes, walk up to the reception desk, and the hotel clerk fetches the customer his room key. There was no communication, verbal or otherwise, between them.

Because of this behaviour, and only this, Tom is almost certain that the man is there on business rather than on vacation, even though he has never met or even seen this man before. Why is Tom so sure of this?

Hint 1:

The clerk had never met, seen or spoken to the man before, and was not aware that he would be arriving on that day

Hint 2:

As the man is standing at the reception, the clerk also knows which company the man works for, but Tom does not

Hint 3:

The man is attending a conference

• If every answer produces an excluding edit this isn't a puzzle. It's "guess what I'm thinking". Apr 8 '16 at 1:25
• Honestly, despite answering, I voted to close several minutes ago, as the question is too open-ended. There is not enough evidence pointing anyone toward the expected answer. The fact that the question keeps being refined to negate any existing answers further goes to indicate its poor quality. Apr 8 '16 at 2:08
• Edit history says otherwise. :\ Apr 8 '16 at 2:16
• Yeah, I was about to have him riding in on a new segway prototype that gave away the company. Apr 8 '16 at 2:21
• I still like the segway answer better
– ffao
Apr 8 '16 at 2:38

Clerk and guest say nothing because...

The man was wearing a badge that revealed his name and who he worked for.

He was attending the same conference and recognized the lanyard but could not see his badge.

• This is essentially correct, although Tom did not need to see the badge -- he deduced that the man was wearing a badge from the clerk's actions Apr 8 '16 at 2:37
• @Karnivaurus Nitpick for a nitpick, I guess. Thanks for the check, though. Apr 8 '16 at 2:40

The man is an undercover police officer. He flashes a badge and takes the room key that was about to be handed to his suspect. Without a word he escorts the suspect to the room where nefarious goings on have no doubt occurred.

• While I still like this answer,+ I admit it predates the 3rd hint. Apr 8 '16 at 2:46

The guy was dressed in a neutral suit, had a suitcase and a big label saying 'Hotel Inspector' on it.

• LOL good one :) Apr 8 '16 at 1:05

The man is wearing his conference badge around his neck. That tells the clerk and Tom all they need to know.

• Nice work! But... I think I beat you by several seconds. *Shameful nitpicking* Apr 8 '16 at 2:34
• Well done. Actually, Tom does not need to see the badge, only the clerk. Tom knows that the clerk must have seen the man's name to fetch the correct key, and therefore knows it must be on a badge on him. This tells Tom he is there on business, even without seeing the badge himself. Apr 8 '16 at 2:35
• Feel free to give the tick to feelinferrety. I'm still more proud of my other badge answer. : ) Apr 8 '16 at 2:36
• Aren't you a shining knight. +1 to the cop! Apr 8 '16 at 2:39

Because there was no exchange of communication...

...it indicates that the receptionist probably recognizes the guest. How could the clerk recognize him unless he has been there many times before? Vacationers are not likely to visit the same hotel so often, but people who make frequent business trips tend to find a favorite hotel in their most-visited locations.

• Tom is more confident than this; some people do revisit hotels for vacation, even though more do for business. Apr 8 '16 at 1:00

the new customer booked the entire hotel for the month just for himself so he could be alone while he worked on the new book he's writing. No other customers arrive because the hotel is closed. Thus this had to be him because he made it past the entrance.

• But this could be for vacation too. Also, the hint explains that the clerk was not expecting the man. Apr 8 '16 at 2:00
• @Karnivaurus Edited to make it job related and day independant. Apr 8 '16 at 2:04
• But how did Tom know that the man had booked the entire hotel? Apr 8 '16 at 2:06
• @Karnivaurus edited to make that clear Apr 8 '16 at 2:09

Almost certainly not it, but it fits (as of the most recent revision):

Tom guessed the man was there on business due to some identifying feature, such as a lanyard or name tag. The clerk knew who the man was and what room he was staying in because, despite the fact that they had never met, the man had been described to the clerk ahead of time, and had a very distinctive set of features that were unlikely to be mistaken for anyone else.

Immediately after I hit the post button, an answer was selected.

• That works for me. Apr 8 '16 at 2:38
• I'm notoriously against closing things for being too broad, but OP does have a point above about the "right answer" to lateral thinking puzzle often being the most elegant one that relies on the fewest assumptions - my answer technically works but introduces more new pieces of information Apr 8 '16 at 2:41
• To be fair, OP also kept introducing new pieces of information. :\ Apr 8 '16 at 2:42
• Minimal extra assumptions sounds good. The reality is minimal is subjective. Whatever the OP hadn't thought of seems to be more expensive, assumption wise. Apr 8 '16 at 3:19
• My issue with this is that, while aliens coming to Earth is a highly unlikely assumption, a hotel inspector coming in with identifying clothes or someone flashing a badge seem entirely plausible. The OP's solution is not more likely or more satisfying than any of those in this case (having attended some conferences, the badge was always given to me at the check-in counter.)
– ffao
Apr 8 '16 at 3:36

It's 5am. No one has fun at 5am.

People urgently trying to get to a morning meeting however might call ahead while parking their car to be sure there are no delays at an otherwise deserted check in desk and thus be recognized at the desk without a word.

Plus the guys in a suit. Who goes on vacation in a suit?

• Interesting, but not what I had in mind. How would Tom know that this man had called ahead when there was no exchange? Apr 8 '16 at 0:57
• There was no exchange at the desk. There was recognition. No recognition. No key. What you had in mind is not relevant when you use the lateral-thinking tag. Apr 8 '16 at 1:03
• How would the clerk recognise the man if they had only had a phone conversation before? Apr 8 '16 at 1:03
• Timing. It's 5am. Deserted. Apr 8 '16 at 1:04

Because there was a comic-con going on and nobody other than business people would show up in neutral clothes.

• nice, but explain how he got the key without a word. You're nearly there. Apr 8 '16 at 1:50
• I take an issue with this answer, as PLENTY of attendees would do so, as would other, non-business, non-attendees. Apr 8 '16 at 1:52
• @feelinferrety I didn't mean to offend anyone.
– Carl
Apr 8 '16 at 1:54
• It's not so much an offense as it is poor logic. Apr 8 '16 at 1:54
• Nice answer -- but as @CandiedOrange says, the clerk somehow knew which key to fetch Apr 8 '16 at 1:55

The guest didn't need to say anything because...

There is only one room left unoccupied when the guest arrives, so the clerk hands him the only key left with no conversation needed.

Tom thought he was there on business because...

The man only had a laptop bag with him.

• Nice thinking! But how does Tom know he is there for business? Apr 8 '16 at 2:03
• Derp. Got to thinking too much about the clerk/guest problem and neglected to address the observer/guest problem. Apr 8 '16 at 2:04
• Also, how did Tom know there was only one room left? Apr 8 '16 at 2:04
• Tom didn't have to know, only the clerk did -- that's how the fellow got his key without saying anything. Apr 8 '16 at 2:05
• Yeh you're right actually. Although it doesn't explain the business thing. Apr 8 '16 at 2:08

It might be:

The man is the owner or one of the owners of the hotel. The owner only goes to his hotel for meetings or conference

• But how does Tom know he is the owner? Or that he only goes there for meetings? Apr 8 '16 at 2:29
• @Karnivaurus You didn't say Tom knew he was the owner, just that he was there on business Apr 8 '16 at 2:30
• Yes but Tom in order for Tom to know he is there on business, he needs to know that this is the owner of the hotel. Apr 8 '16 at 2:31
• ok, will refine lol still thinking... Apr 8 '16 at 2:33