You can easily point out guildmates who are not attacking each other with video as proof. I believe there's a case like this (not attacking guildies/friends) not so long ago.
-- If you know the rules, you will not dare go inside dksquare then suddenly your mum told you to eat and will shut your pc off if you will not go in like 1 minute and then you afk
-- If you know the rules, you will relog your character so you will not be banned.
In boosting/dual logging, It's also easy to point out
Example: 1 guy at Miseria is not in raid but still getting points