In my experience as well the issue has not been that I was banded by another doctor, but that it was in Mexico.
Any doctor or fill center can eaisly draw up a liability waiver that states that the patient understands the inherent risks and that they understand all possible side effects and that you can not sue. They can make each patient sign and date that and it is legally binding. It's not that these doctors "can't" do the fill, or don't want to be legally responsible, it's that they want to get the word out that there are repercussions for not paying to get it done by them. Like was said earlier in this post, the docs don't want our few hundred for the fill, they want our $18,000 for the surgery. It's a "punishment" of sorts for going out of country, IMHO.
Absolutely, if you have not had surgery yet, call around and find out ahead of time who can/will do your fill. A good resource is www.obesityhelp.com - then click on "find a bariatric surgeon" in the upper left hand corner - click the "Lapband" link and then you can choose a state to search in. Like Paula said, with the price of an airline ticket these days, you want to be sure you know you options ahead of time!