It is so that smurf accounts and accounts that were created and are not played in low levels can get deleted. I know it from friendly bug, some of my friends created new facebook accounts so that they could play friendlys all the time vs them but if you don't login then, they will be deleted. Not if you are in an association though...

I dont care about this, but I assume that this is the true reason, just to not have so many clubs dumping around.