I wore mine at Leigh-on-Sea at the weekend, and a fella in a session buttonholes me, saying "I've been looking for that address - they've got one of my songs on the Digital Tradition without saying it's by me" - so we'll be hearing from him no doubt. But, quite rightly, he felt honoured rather than indignant.
This week T-shirts are fine. But most of the time sweat shirts are what we really need. Or weskits.