By stating that it wasn't a threat, you were obviously trying to hide the fact that it was. Whee, sarcasm. And I wouldn't be rude to anyone when I'm working, only if they act like you. Wheeeee!
So you're saying that you're actually a girl and have a muscular, ANGRAH biker dad who goes to stores and beats up rude customer service employees? I'm not seeing the threat here. You need to learn on how to word your insults/threats. But whatever, I love conversations like these.
Also, I'm pretty sure the job I'm hoping to get in graphic design won't care if I got fired from some Wal-mart/TRU/Target for yelling at some annoying kid angry about not finding his toy.
I guess so, but people close to him have said that they would rather not have signatures about it. Really, out of respect to him, you should take them down. That's just my 2 cents...