Note: I have invented this puzzle myself as far as I know. I'm certainly not aware of having read it anywhere else. I have no idea whether it will be hard or easy.
A man is imprisoned in a strong steel cage with a steel floor. The cage is open at the top but the vertical bars are greased and cunningly designed and no matter how hard he tries he will never be able to escape that way. He has no access to tools nor anything he can make tools from. Every day he has access to adequate food, water, bedding and toilet facilities (Edit: Plus shelter from the elements), but none of these can be used to break out of his prison.
Outside the cell is another similar cell that encloses it. It has no facilities. Outside that is a yet larger cell enclosing that one. It has no facilities. This goes on like Russian dolls for some time.
The man can see the outside world through all the bars. He knows that if he can escape from the cages he will be released.
The guard throws him a key-ring with keys to all the doors of all the cages and departs back to the guardhouse. The man desperately wants to escape.
Instead he stays in the inner cage for a long time before leaving. Later he ventures into the next cage but soon returns to the inner cage and stays there for a long time. Then he ventures to the next cage but returns once more to the inner cage. He repeats this as many times as there are cages.
Finally he walks free and never returns to the cages again. On the way out he takes out his wallet and pays the guard a substantial amount of money. He is safe and free for the rest of his life.
What is going on?
Clue
The man and the guard are the only two people (or creatures) involved in the situation but there was a mobile crane in use just before the above story starts. It also leaves before the story starts. However the crane was not used to lift any part of the cages or other equipment and was not used to help the man escape in any way.
Notes
The cages are plainly built with unclimbable bars and are roughly square-shaped. Each has a single door. If the cages weren't there, the man could easily walk to the guardhouse in a couple of minutes.
There is nothing designed to frighten or hurt the man about the setup.
EDIT to address questions in the comments.
@Display name - This is describing a real man in a real situation. Whether it will ever happen in real life is debatable but it just might.
@CR241 - The man is not wrestling. He is alone in the cages the whole time.
@Displayname - The cages do not reach all the way to the guard house. They are fairly close in size with a relatively small gap in between. It would have been more sensible of me to make them square but all of the same height. I just didn't think of that. The height just needs to be enough for them to be unclimbable.
@fakedad - You ask if the geometry of the cages is important. On thinking about it, I've added that tag. So yes. However he can't climb or break out and the only exit to each cage is its door. That is why he needed the keys.
@Hugh - Having looked at the definition of the story tag, I don't think it comes under that category. Clearly there is a story involved but I'd say this is more of a situation. I'll look into this further though.
@JimM - The locks and keys are well-maintained and are just normal ones that open easily with no special tricks or time-limits. The man can open or lock them at will.
@Steve V. - As long as the man is constrained to leave by the doors and can't break or bend or damage anything it doesn't matter what the cages are made of.