I usually have a Mont Blanc ballpoint in my shirt pocket and it has a very pointy end which I am sure would do a lot more damage than a set of nail clippers. Never ever had anyone even look at it.
jimworcs - good point, the irony is lost on the jobsworths. How about all those glass wine bottles washing around the cabin, one of those would make a mess of someone's face, used strategically.
I had a flight a couple of years ago, on SQ somewhere in Europe, plastic on the way there and metal cutlery on the way back. Presumably terrorists dont get on planes in Europe. The CC said it was that country's regulation. Bizarre.