In February I was flying back to LAX from a small regional airport in Arkansas. They only had the walk through xray scanners. I had on a tank top (no bra) with a pull over sweatshirt over it. When I was ready to walk through the scanner the TSA gal asked me to take off my sweatshirt and I politely said no. She motioned me to come on through. Once I got through she told me they were going to do a pat down ( I knew it was because I refused to take off the sweatshirt). I told her no, they were not going to pat me down and quite the polite argument ensued. Finally she just patted down my top back, under my arms, and neck area.
I got lucky because it was a small regional airport. Had it been LAX I probably would have wound up in jail. Lol
That is my one experience with the TSA and it was great fun.