Let's assume that 60-80% of Americans think this immoral. Let's assume that 20% of Americans are disgusted in this and willing to act. Such a loss could be potential. Given that most Americans have been here longer and have larger savings (due to higher education rates/inheritance), it would have a much bigger effect. Boycotts are one of the most effective methods we have for these kind of situations.
Morals first, laws second.
Now a website specifically for this would be good. Any webmaster here? My thought are you have a website on businesses that support illegal immigration, and you get voluntarys to hand out fliers everyones and a while; just to get the message that these place don't deserve our business.
Thoughts?
Yes, my thought was (and remains): a boycott is certainly your prerogative - good luck with that.