Weekend hypothetical. Just for fun.

You drive up to this hotel, and pull into the open parking spot indicated in yellow arrow, next to the entrance. This is public street and there are no signs indicating that these are hotel-exclusive spots.
Hotel asks if you'd like for them to take care of the car (one assumes they'd move it to a covered/secured garage). You agree, naturally.

The next morning you find the car in the same spot. You check out and pay for the $50 parking service -- the service in this case being that they hand you the car key back.

Does this constitute a valid fee? (I did not and will not contest, btw).