I've had some interesting experience with public paid parking lots with groups on bikes.
1st @ a lot in Lake Placid, NY during an Amercade week...the parking lot attendant said, we charge by the space not the vehicle, so squeeze in as many bikes as you can into each space. Great!
Then in Carmel, CA we did the same but on the way out the attendant said every bike has to pay, even though we shared spaces. The gate was still up, so I ignored him and rode out.
Later, I found out the guy behind me paid my tab. The attendant had threatened to call the police If someone didn't pay.