"We are not actually able to (legally) honor warranties internationally; that is, we are not allowed to ship anything."
Sometimes parenthesis are important!

But, it's worth finding out whether your sister can be the registered owner as far as enTourage is concerned, for just such an emergency. I haven't been keeping track re: who from the second wave has been having hardware issues compared to those of us from the first wave. We do know the power adapter issue was only for first wavers, for example. I think most issues that have arisen in units have been noticed within the first few days.
Perhaps those of you with US buyers could have them do the initial charging and play around for a few days so that if issues arise, they are in a position to deal with enTourage on your behalf. Yes, it's a longer wait, but it seems a fair trade for the person helping you out - they get to play with the machine first!