[peteyspambucket]

Actually, I do have Verizon. I'm considering unlocking it.

If I unlock it, and put a Tmo sim chip in, would I receive calls from both my Verizon and T-Mo numbers? I wouldn't think that was likely. But I am wondering how the phone would "know" which number to use if I did not change the setting in "Mobile Network Options", since you suggested it did not have to be changed.