I'm only talking theoretically, I'm not about to do it. I don't think my friend had upgraded to L2, and I'm not buying a second account.
The multi-boxing vs pre-arranged alliance are essentially the same issue to me, but whenever I've said anything to anyone about it, they've said "So what? It's not against the rules."
In fact, a couple of times the multi-game alliance people have defended their actions, saying of course that's what you should be doing. Playing with your friends, there's an invite button for a reason, why wouldn't I want to have an alliance where I know I won't be betrayed? etc etc.
Depending on when the player signed up, they don't even know the term multi-boxer or multi-game alliance, because the rules they read never had it in.
But there's no way around it most of the time. You join a game, there's a very real possibility (for me, it seems to be about 30% of the time, although it's been more like 75% recently) that there'll be an alliance out there before the game starts. Every game I've played, it's the alliance that gets their shit together first that wins. Any group that starts too many individual wars, or doesn't concentrate their firepower early, loses.
What worse, is you don't know it, and those players aren't always stupid, they don't broadcast it by not talking to anyone else. They still form other false alliances. So everyone is playing a game of trust and faith except them.