When I travelled to Latin America and Europe in the mid 90s I was pretty much ashamed when people asked me about this initiative (people there had read it in the news). It was widely inconceivable to them, and unforgivable too, that someone would be asking children to show documentation before being admitted to a public school.
Immigrants don’t come for the “free public services”. They come here because of the wage differencial; in other words, they come here to WORK. They contribute with their hard work (have you seen any born US citizen lining up for toilet cleaner jobs lately?) and they contribute with the sales taxes they pay in the countless transactions they are involved in, not to mention income tax withheld that they forgo entirely if they are undocumented.
The problem we have is that the laws are not in agreement with the economic reality: there are willing workers south of the border, and willing employers north of it. To pretend that this economic reality can go away by decree is naive, to say the least.
In fact, one of the few sensible initiatives proposed by Bush was his guest worker program; which would regulate, rationalize and institute order in an activity that is impossible to ban by decree.