I would suspect that they were marked present for the whole day so that the school would get the money. Someone needs to demand an audit to verify that the school officials were not committing fraud.
It's a nearly unverifiable crime.
A person or group would have to collect evidence (photos or video) supporting the assertion that school-age kids were in the rent-a-mob protesting around the White House on a school day. The students would have to be ID'd and matched to DC school attendance rosters for the affected schools. Without this type of evidence or a pile personal statement, there's no way to prove that the teachers and other education officials were commiting fraud.
In addition, there will be a contingent of useful idiots in the school system, the media and local politics that will hamper these effort and argue that the investigation will consume more money than what was lost by the student's truancy.
From the 60s to the present, civil disobediance by college students has evolved into the "perfect crime". I can say this because during a rally, student protestors are "stealing" countless credit hours of tuition that are paid for by their parents, Alumni-backed scholarships and Federal student loans. The protestors know we're the suckers. Now they're applying the same tactics on the High School and Middle School level.
Now keep this day in mind whenever student loan amnesty ever comes up in a conversation.