Joking, of course. It struck me as funny to be banned from a site I have never accessed.
It could be my browser settings or something as simple as site limits placed upon snooping guests.
Well it's possible actually to be banned without ever being there before, as someone else uses a similar IP address range that your ISP account uses, and the board has banned that entire range of IP addresses.
But usually it indicates that you're been banned with a message saying you're banned or something, so I doubt that's the case.