Just a few thoughts, and no I don't drive or own a hybrid.
Providing parking spaces is good customer service, doesn't matter if it has electricity, is covered, lacks potholes or whatever. Customers will go to the stores that provide the best product and service.
Providing elec is nothing new. 30 years ago I lived in Anchorage, Many shopping centers provided electricity for block heaters. The centers that had elec provided had full lots in the winter. Those that did not had empty lots. You pay by shopping in those stores that provide the service.
The same way you pay for the surface, striping, lighting, crosswalks, landscaping, maintenance etc.
About enforcement- Of course the police won't be enforcing hybrid parking. They rarely, if ever, enforce handicap parking.
But private lot owners can enforce rules in their lots and many if not most public lots are managed by parking companies. You can be ticketed, booted, or towed.
Also, hybrids do pay taxes. Remember they use gas and electricity. So they are paying the gas tax. Bully for them if they get good mpg. As far as totally electric vehicles. Here owners pay an annual fee when licensing their car to make up for the taxes they don't pay at the pump. Seems to me that gas vehicles get the break. At least I can choose how much unnecessary driving I do.
Imp