The problem here was only the sig ad, nothing else.
Yes, but a second warning would have been enought. Not a ban.
Sometimes mitigating factors should be weighed when making a decision like that, and given SJ's reputation I would think a warning should suffice. I agree that the sig is a problem but I think a ban is far too severe for this type of offense. I see Spoetnik and Gleb Gamow consecuposting all the time. All the time. They don't wear signatures though.