I always treat bike racks as public parking. The only time I'd ask is if it's clear that the business is using it for some other obvious purpose, like putting bikes on display for sale.
I also have no problem locking my bicycle to random things when the business/shopping center fails to provide appropriate and close parking. This includes but is not limited to signposts, fences, and trees. I am also a jerk.
Last edited by wipekitty; 11-15-17 at 09:19 PM.
Reason: Keepin' it positive =)