I have never received a pat down due to the pump. When going through a mag, it almost never alerts in the first place. When going through a scanner (and therefore need to hold the pump above my head), all TSA does is swab the pump (or give me the option of using my hand to swab the pump and then swab my hand) and run that through the spectrograph. Doesn't mean you won't be subject to secondary search for some other reason, but don't worry about it. If you do worry, remember that you can ask that the pat down be conducted by a TSO of your sex and in private. If you need a trash can, bin or other container near you, I doubt that you will be denied. Just be nice and non-belligerent and you will be through the checkpoint and at your gate before you know it.