Bit""&ng on here is probably preaching to the converted.
It is worth trying to be pro-active.
Even worse, was the number of student pilots (some on solo navex's)
So, this was an opportunity to establish which school they were with and which instructor. I would make a call to their CFI. Both the student and the school might "learn" a very worth while lesson. Isnt that the object of airfields "mentoring" students.
Train the student properly and you will end up with a better pilot.