I know some restrict it based on current employment. Restriction based on previous employment at a site is way too restrictive in some cases. There's only a handful of hospitals in certain areas, and if someone did basic work for the hospital before, he or she is now restricted from ever going back as a learning experience? Doesn't make sense doing that. I would say that with regards to community pharmacies (which usually outnumber hospital), every attempt should be made to gain experience at a different site (same chain's fine), unless there's some sort of extenuating circumstances.
UIC is stricter. They say you can't go there if you ever worked in the pharmacy's department. There are exemptions. Let's say you work at a Walgreen's Pharmacy. You decide you want to do a corporate or WHI rotation with them; that is fine.
Yeah, we had to list every we had ever worked so they could avoid placing us somewhere we'd been. I don't think it was much of a problem for anyone in my class.
We can work at the same company, but not same store. Also, for us hospital people, we can do rotations at our hospital but the preceptor can't be our boss.