Clearing up a few things..

[Quall999]

MS have always been banning for an unlocked HDD. That is not the new protection they have.

MS scans your xbox for the HDD information, like model number, etc... If you sign on live and they detect a change, you will be banned (supposedly). This makes it almost impossible to be unbanned.

If you have already been online and want to upgrade your hdd and go online still, you have a chance of being banned. Your best bet is to find another xbox that has never been online, then upgrade that HDD. Switch dvd-drives if you want too. Then sell the old xbox.

I have been going online with my upgraded HDD since the "new protection" was introduced and long before I upgraded HDD's. However, I believe I upgraded before the HDD information scans, so they did not detect a change in my HDD.