So far this year, I've been in the Denver, Minneapolis, and Milwaukee airports and have managed to walk around barefoot without incident. This does not include going through security, where people are required to take their shoes off anyway.
I've read reports from the SBL forum on Yahoo that a few people had a little trouble boarding planes while barefoot, so I put shoes on when boarding and leaving the planes. There were other times when I simply didn't feel like carrying my shoes, so I wore them instead. Even so, I went barefoot a significant amount of time, enough for people to notice that I was barefoot, and no one said anything to me about it.
