The pharmacist in my old town said exactly that. "its YOUR responsibility to check your purchase BEFORE you leave. Once you leave my counter, I have no idea what you do to this stuff, and therefore you lose your right to complain." He really said that! So, from then on I made a heinie out of myself and stood to count and examine each prescription before I left. What a jerk! it was the only pharmacy for many miles around, and I had to watch him like a hawk. I put him on notice that I was not going to walk away quietly.

I do understand there are folks who tamper with thier stuff in hopes of tricking a pharmacy into a free refill or a settlement even, but you cant distrust all your customers, can you?