I would also add that the stories you do hear about (e.g., Rush Limbaugh) or arrested doctors usually involve someone ratting out the person, or related deaths.

When I first discovered OPs a couple years back, I jumped the gun on switching from 5/500's to Vicoprofen (different OP/doc), but didn't realize they were using the same pharmacy (TDI I believe). TDI simply said they couldn't fill the new order until X number of days had passed. Other than being a little embarrassed, I've since stuck with one OP.