I have personally only set off the alarm once and it resulted in a pat down. The female officer was awesome and very understanding. She basically didn’t even touch my breasts. However I have a daughter and she sets off the machine (metal detector >12) for a “random search” every single time we fly which mostly ends in a pat down. We flew a couple months ago, and she had some action in the region. And the woman who patted her down (a child) was EXTREMELY thorough. She was standing there forever while this lady parted down her (small, developing) breasts for like a solid 12 minutes and payed little attention to the rest of her as if the search was pointless without checking her breasts.