Because I told them!
I reported hundreds of bugs and issues in previous Betas and on Live Realms. They just have to make a note or flag my account.
But it makes no sense to pay for the upcoming months to have a tiny chance for a random invite if I don't like to play anymore. Most players are gone and I could not manage to get past the first wing of Icecrown Citadel with my old guild.
As soon as 4.0 hits Live Realms or when I get a Betakey I will renew my sub (if needed).