Some people have been getting in to the Call of Duty 4 using a glitch that eBay sellers and friends of those already in the beta have been taking advantage of. It seem they are now being banned. The glitch involves giving someone else (either your friend who is the beta, or the people who have been selling this procedure on eBay) your account login and password. They then do some tricky stuff and the end result is that you are able to download the beta and play.
Microsoft and Infinity Ward
have caught on though and as you can see from the screenshot below, people are being banned.
