if you know the person, like the person and think they'd do the same - then chop.
If not take the pot, it's your pot at the end of the day.
So you'd chop it with your mate and keep it from anyone else?
Saves you getting cold in the car park, I suppose.

A for me. I'll never be rich.
Yeah pretty much. You have to assume that the default for someone you have never seen or met before would be to keep the pot, I've seen it happen where the guy has turned his hand over and laughed and celebrated how he has won half a pot more than he should.
There is nothing immoral about keeping the pot, unless it's an absolute beginner player who genuinely doesn't know better in which case id chop and tell him try be more careful, but at the end of the day he's mucked, the pot is yours those are the rules there is no grey area, if you give half the pot then you are doing him a favor.
So the Q is, would you like to do this person a favor?