I'm no fan of open hostility. I believe in sportsmanship and being cool to visiting fans, even when they are hated rivals. I've shaken hands with visiting A&M fans, drank beer with Nebraska and Iowa State fans here, I even told the UT pep band in 1998 "good show and good luck".
With all that said, I highly recommend NOT wearing a ku shirt in Aggieville. I only say this not because I fear for anyone's safety. That's not the problem. I just don't think you'll have an enjoyable time there wearing it.
But if you can handle excessive ribbing, by all means go for it. I wouldn't. :(