Why-did-Google-stipulate-that-the-developer-should-be-a-citizen-of-USA-in-the-terms-and-conditions-of-pre-ordering-a-Google-Glass-for-$1500-yesterday?

Why did Google stipulate that the developer should be a citizen of USA in the terms and conditions of pre-ordering a <a href="http://glass-apps.org/google-glass" title="Google Glass">Google Glass</a> $1500 yesterday? <br/> http://www.quora.com/Google-Glass-4/Why-did-Google-stipulate-that-the-devel…terms-and-conditions-of-pre-ordering-a-Google-Glass-for-1500-yesterday