Never confiscated, but apparently sleeved Magic the Gathering cards look like explosives to the TSA. I kept getting "randomly" searched and being late for flights until I finally asked the dude why I kept getting "randomly" flagged for additional screening and he told me. It was also frequently cold when I was traveling and my suitcase was often left in the trunk of a cold car all day while I was at work and that also makes them suspicious of my belongings.