It's your responsibilty to remember your lock. Their busniness store is a business place, not a garage. You forgot your lock, that's not their fault. Maybe the manager was a jerk anyway, but should you drive your motorcycle in there too?
It wasn't Radio Shack that forgot your lock.
I went to Costco the other day on my bike to pick up a contact lens order. No bike racks anywhere. I asked the door person if there was anywhere I could lock my bike. She said I could bring it inside and leave it, but don't do it again. I thought that was stupid, not having a bike rack in Seattle, where so many people ride, then I thought about it... Who in the hell rides a bike to Costco? Normally people that go there buy mass quantities of stuff in bulk! People fill cars and minivans with bulk products when they go there! What was I thinking, expecting a bike rack! Damned presumtuous of me.