I don't have an answer...I had an appendectomy in 04' and the clips are now calcified in the cecum. Hurts like PMS, but there hasn't been PMS in years. I think the clips are not as innocent as they are portrayed.
Clips are routinely left in in many surgeries including gallbladder and other surgeries. Docs aren't required to say anything about it. It's probably assumed if you want to know, you'll ask. The clips are the most time-efficient and direct way of completly 'clamping' something off so that no leaks will occur after the surgery site is closed and the patient can begin recovering.