I was banded 1/07, have flown several times, and have set off the alarm once, for different reasons, ie: watch, metal on me. I have never mentioned my lap band, and I wouldn't. There is no metal on the band, and it is not their business, as is a IUD or any other personal implant. The band itself would never set off the alarm. I would not even mention it to the airport security, as this may alert them to a potential problem.