I seriously did not think it would as it's not an underwire, but as soon as I saw the big grins on the two female TSA agents running the machine I knew. Worst yet they pulled me over for a pat-down. A male TSA agent said "We had an alarm on your back.", (I am guessing the hook and eyes) then had me turn around facing the two grinning female agents and ran his hand down the center of my back, then from the center out right on my bra a couple times. He said "I can feel something going across your back", I simply looked him straight in the eye and said "I am wearing a bra", he just said "okay" and let me go.
So it's not something that is going to get you on a "no fly" list, but be prepared as they do not give under-dressers the same leeway about metal hardware on underwear as they do for a GG.
I don't know, maybe if it was actually an underwire bra they would have let it go because it was obviously a bra?
Anyone else have any TSA stories to share?