many (probably almost all) people who subscribe to the $65 unlimited int'l data get it with a one year commitment.

That said, I have never had a problem switching back to the domestic plan. I just call 611 and they switch it back.

the process of putting it on/taking it off, can take anywhere from 10-25 minutes on the phone. So if you are going to be doing a lot of back and forth, I would recommend just keeping it on.