Public school busses take students to and from protest?

Via Michelle Malkin, I've learned that Tucson school busses at minimum transported students from the pro-illegal immigration protest.
I recognize that Indymedia isn't exactly the most unbiased and reliable source, but a photographer does indicate that school busses took students to AND from the protest. From might be an issue of public safety. To is absolutely outrageous. Consider this a developing story.
The last time I attended an MLK march (shortly before the 2004 primaries), UA Cat Trans transported people from Reid Park back to campus. I hardly think this is equivalent to supporting Martin Luther King, despite the political overtones tainting that particular march.