no harm sticking it on a supermarket as long as you use the shop. coffee shop ones will be best ones i guess. an hrs free charge will likely give you 20+ miles free while you get a nice rest, coffee and cake etc, or even a meal. Or just do your shopping. Just using it without using shop is if nothing else morally wrong.
Current Car: Hyundai Kona Premium EV...2 way 40kg hoist
Last Car: Toyota C-HR Excel Hybrid...4 way 80kg hoist