[wjackson81]

I just went back to re-read the thread and it looks like jibi is the person I was looking to back me up on this. Only one person not on Tmobile reported a problem and they said it just wouldnt let them on EDGE consistently, and therefore their SIM hasnt been completely blocked.
After a careful re-read of the thread it looks entirely plausible that Tmo is monitoring their network for the beta OS's. I would assume that the reason it was on this version and not others is that this version is close to the final release (opinion based on stability). On all other versions people have complained about the version being too buggy to be worth the time, whereas I have not noticed any major issues with this release.