This is ridiculous. Target the promotion to US-only.
Now, if your page is liked by folks in foreign countries then you still may get (organic!) foreign likes, but you shouldn't be getting any paid foreign likes.
tldr: layer on US-only targeting
Now, if your page is liked by folks in foreign countries then you still may get (organic!) foreign likes, but you shouldn't be getting any paid foreign likes.
tldr: layer on US-only targeting
Every time I run Facebook ads I target them to Raleigh, NC, USA only. Almost all the resulting clicks are foreign (according to the IPs I see in my analytics).
YMMV
Example: http://i.imgur.com/khYDf.png
I'm a page owner (130k+ fans).