Well I don't take such a harsh view on that one (permaban). Maybe because when I started flying in 96, the common gag was to tell newbies to press "p" for power, when in that game it was for parachute The counter argument would be that anyone who uses windows should have a clue what alt-f4 is. I agree though that is a poor welcome, and that gag may get a player booted from the TA.
It isn't fair to assume that anyone, let alone everyone, knows what Alt-F4 does in windows. I'm fairly computer saavy, and I never ever ever use Alt-F4 to shut a running program down. As far as I know, Alt-F4 is more a tool for folks who are doing something they probably shouldn't be doing while at their desk at work, Alt-F4 to dump the game when the boss comes around.
You may view the Alt-F4 as an harmless "gag", but put yourself in the shoes of a new player. You've been online for a bit, crashing and/or being shot down repeatedly. You ask a question that some tool thinks you should already know the answer to and you get fed the Alt-F4 gag.
May seem harmless, but is it really one more frustration heaped upon a two weeker that HTC wants? It was my understanding that the end goal for HTC is that those two weekers actually pay a subscription at some point.
I say perma-ban, make it widely known that it is ban worthy. The issue goes away.