Just yesterday I had a pat down from a TSA Officer because they detected some sort of substance in my carry-on bag. As a result I needed to be patted down and it was a more thorough pat down than I've ever experienced. Before the pat down he explained the rules and procedure to me. Then after the pat down he said that he'll need to swab the gloves he had on to make sure there was no illegal substance on them. Of course there wasn't - but it got me thinking. I did not see him put on gloves with my own eyes, therefore the gloves could have been contaminated with something not from me. If selected for a pat down in the future, can I ask the TSA officer to put on a fresh pair of gloves with me watching him/her put them on?
I always request clean gloves before they touch me or any of my possessions and they have to accommodate you.*
Everyone should request clean gloves every time to prevent any cross contamination. Current procedures are a huge pathogen vector as well.
*For clarity, I've never seen this documented, but various screeners have told me as much.