Should a store have their live rock attached to their systems?

[Aquattro]

When I buy rock, I want it fresh, uncured and not having been in contact with systems other than the rock bin. Having bought fish that had velvet, I know that the likelihood of an entire system having some disease is fairly high, and I don't want to introduce a fish disease when I didn't even buy a fish.
Personally, I would not buy rock attached to the main system.