Maybe this symbolic "boycott" will have an effect in some of the low-rent districts where the illegals live, but I'm guessing it'll be hard to tell the difference in my part of town. I'm expecting about zero economic impact, since stores catering to that community stayed opened late yesterday and did a brisk business in anticipation of today's holiday.
The way I see it, many of these illegals want it both ways; they want money here by doing unskilled labor (nannies, car washers, restaurant help, cleaning crews, fast food workers) but don't want to renounce their Mexican citizenship, don't want to Learn The Language, and certainly don't want taxes withheld from their (mostly cash) wages.
The result -- they send $US billions back to their families in the (even more) politically corrupt*, poverty-stricken nation to our south, so that even more of them can Escape. Eventually, the old immigrants will retaliate against the new immigrants, whose increasing numbers will drive the oldsters' wages down.
*Corruption is widespread in Mexico, where they make Karl Rove's manipulation of US laws look like a stroll in the park.By Friday ("Cinco de Mayo"), most Americans will have forgotten about today's Event. May 5th is a bigger celebration here than in Mexico. Many stoopid Americans think Cinco de Mayo is Mexican Independence Day, which it ain't (that's September 16th). The official holiday is "Aniversario de la Batalla de Puebla" which has become an equivalent to the Irish' St. Patrick's Day, where the goal is for Americans to get drunk. Big woop.