So by your logic, I cannot play with a higher leveled friend on borderlands because it will give me more xp than if i played with people my own level. Hmm..hardly seems right for a gaming COMMUNITY. Lay off the rules, it's not like he's going to a cod game and boosting headshots. He's leveling up in a game that is only campaign. There is no leaderboards and no matchmaking (outside of campaign). Also, you probably don't know this but Gearbox supports modding for borderlands 2. So are we therefore not allowed to mod a game that the developer encourages us to, even though it's against the xiled rules? The rules aren't meant for games that are campaign based like borderlands, they're meant for FPS and games that have leaderboards that will be directly affected by somebody boosting.
Markovzero feel free to add me, as I would gladly let you join my game to level up your siren.