I don't know of anyone who has had the TSA actually open a film box on them unless they are not paying attention. All you have to do is tell them it is film and they'll swab it instead.

The point about putting your film into a clear plastic bag and passing it through in a separate bin from your main carry-on is a good one, so that they don't stall and cook it in the X-ray chamber.

I don't fly as much as a couple years ago but mostly my film got swabbed or ignored. If you have a lot, allow extra time.

I'll still argue that it is safer to keep the film in your possession than to be shipping it to third parties like hotels, etc.