Technically, yes criminal conversion is certainly a thing. If the laptop was expensive and you lived in a really low crime area where the cops were bored that might get pursued. My experience is that cops are practically more likely to say, absent a court order, to sue the person because it’s he-said she-said. It’s just too much effort for a potentially muddy situation.

You’d be surprised how often things that are theft/technically theft are not actually pursued by police in the US. The property crime clearance rate (resulting in at least arrest) is <15%.

Holding onto a rental car, on the other hand, is both expensive and cut-and-dried enough (contract states definitive end date ahead of time) to be a bad idea.