Really? The clothes are my least favourite of the swag items. Send me it without the company logo and it's a great gift. But if I have to walk around looking like I'm in uniform then I'd rather buy my own.
When I lived near a large metro area, I liked to hit second hand stores, mostly thrift stores, to pick up really cheap T-shirts. When there's a lot of school districts concentrated in one area, there is often a nice selection of older style logos of local HS teams, which is what I was after. I was fully grown by my junior year, so I can still wear kids' clothes. Anyone that noticed my flare assumed I was local and from that area, so it was a cheap way to assimilate and be left alone.