To mbachur:
Two words: cell phone. Another two: phone card. Another few: toll free home phone number. There are possibilities.
So the scenario I see is, rebbe sees boy may have problem.
In town rebbe thinks: I can ignore this, he has his parents. Heck, I don’t even need to share my reservations with anyone.
Out of town rebbe thinks: I must not ignore this because this boy is far, far from home, and I have been invested with the sacred charge of en loco parentis.
I get it now.