Sounds like people would pay for a small, readily-accessible private space. At first I thought this could be better served by having a proper space and building to house these spaces but maybe, unintentionally, parking a bunch of cars around for people to rent is actually a much lower barrier to entry than dealing with zoning and inspections and regulations.
It wouldn't have to be much larger, though it would probably need some kind of small A/C system, like you'd find on top of an RV. Put a bunch of batteries and/or a small genset under the seat area, a dropdown table on the door, a plug for power, and maybe optional 4/5G wifi. Add a credit card reader on the outside to take payment. Put a bunch on trailers and drop them off in places...
There's gotta be a reason why this hasn't been done already - none of the tech needed is that special, most of it is already "off the shelf". There must be some kind of laws or regulations preventing it?
