I have an iPhone 4 that is locked and tied to AT&T but I also have a 2G that I'd like to use occasionally. The 2G is fully pwned, that is, hacktivated and baseband unlocked. Will putting my 4's SIM into the 2G and using it affect anything regarding my plan or what phone is registered to my account? I assume since the 2G is unlocked there won't be any activation issues, but I want to be safe and leave everything with AT&T unchanged. Is this possible?