By my revised estimate: 2400 students on the trolleys coming from the southernmost station near the border.

“Thousands” crossing by car driven by their parents. Say 3000?

“A thousand” by car driven by students themselves.

We’re up to 6400 students, or 3.2% of entire student population. If it’s concentrated in certain districts, it doesn’t seem to be a county-wide issue, and the total number of students is relatively small compared to county population.