When I flew back to Iceland, there was a guy who literally had a red hat (or fedora) on. Initially I thought I should ask him whether he’s a user of Linux – guessing some “red hat” connection, but then I saw his t-shirt. It had the logo of the GPLv3 printed on it and the usual propaganda that comes with the logo. Perhaps it was one of these.
At this point I decided to avoid any close encounters with the guy, much as I try to avoid encounters with fundamentalist religious people or fanatics with guns. When GPL zealots speak out about the GPL I’ll rather avoid confrontation, though I’d be prepared to make a point on behalf of the non-copyleft licenses when forced to.