If you're an asian in a group, and every-single-one of you has a camera around your neck, I'll probably ignore you or run the other way (have you ever had to navigate through a hoard like that before?!).
If you speak english, I'll treat you the same. Heck, if you're not great at speaking english but trying, I might even be polite.
If you're rude to me, or expect me to speak *your language here*, I'll look at you, say "sorry I don't understand you" and walk off. At least show me that you're trying to speak english and I'll give you the time of day.
Overall, I don't think we treat foreigners all that bad, but you might have a hard time if you don't speak english. Meaning, with the exception of a select few places, we won't speak anything but english.
Of course, having typed all this, I was given the same advice when I went to europe.
I think you'll find, if you don't open your mouth no one will be able to tell you're not American. If you don't seek anyone out, you'll be left undisturbed.
Also, be afraid of retail shopping. It's customary for retail employees to verbally assault every-single-customer with a friendly "Hi how are you can I help you today? we just got product XYZ you might like bla bla bla" Just shake your head, mumble "No thanks", and you'll be fine.
