That's not what the article said, though. The article said the red flag came up when they failed to report to classes. What type of classes, though? Since the article didn't specifically say orientation classes, the reader is to assume they are referring to "class-CLASS," which didn't start until September 6.
I'm not saying I don't agree with your theory, only that in order for it to be true, the article would have been written differently, one would think, anyway.
"University officials must report international students who fail to arrive on campus or miss class regularly."
I don't know the arrival dates for foreign students, do they have to report to an 'advisor' prior to classes starting? I'd think they'd want to give them all those touchy-feely classes prior to the sememster starting. If they 'miss class regularly', than, that's a different situation.
But near the end, the article states:
"The plan was uncovered in its early stages, and sources say there is no indication that the suspects made it into the United States
So, it appears as if they missed their reporting to school date.
Some of the people in the same group did report. Eleven of them split off from the others and didn't show up where others already had done so.