The other side of this coin, people downloading the app to use in their home countries when those countries are un-supported, is much more common. Probably two orders of magnitude more common. Sorry it sucks for you, but I'd make the exact same decision as Google here 100% of the time.
Would be nice to have a third option, that incorporates the country limitations into the purchasing process and warns you when buying the app that it has no data/support/whatever for your country. At least then those of us who do travel frequently and want to be able to use these apps when we do will have that option.
