Also, things that you CANNOT prove in any way should not be said, by both parties.
1."OMG, I AA'd Uber Rave"
2."Stfu newb, no you ****ing didn't"
1. You have no proof, no one will believe you
2. You have no proof that he hasn't, shut up before you start.
I'm afraid I have to disagree with this one. I've said I've AAAd Uber Rave (and I did), and people believed me without my having to produce a screenshot. So no, you don't need to provide proof, just be truthful in the first place.