personally i feel this is bordering on infringement on the rights of the businesses.
Do you consider any car and its contents parked on your property to be under your control? There is a line that needs to be drawn, where does the business's property end and the individual's property begin? Where it is parked, how long it can stay there, and the intention of parking it there are as far as I would give a business owner. However, the right to the car itself and its contents should be solely the responsibility of the owner of the car. Wouldn't you agree?