Posted by Aguzo

Do they allow you to join their team, if you haven't been banned for a certain period of time?

or

Is a ban from, let's say chat blocking, a very good reason to prevent someone from joining, even if it were 2-3 years ago?

I have no clue how strict their requirements are, I've never applied for GP, I think...
Saying this, because I think someone needs to moderate the competitive community.
The best staff, for GPs anyway, are the ones who know the rules, but don't know the players. (They would have no preference towards certain players, so they wouldn't have friends to give free passes to)