No, it's not about what frequency you should do it on. 121.5 is the only D&D frequency available, as has already been pointed out. Or would you prefer the expense of installing an entire bunch of new transmitters and DF equipment?
As for my last comment, it was perhaps a tad strong. However, I have very little sympathy with people who have forgotten what it was like to be a student and now think that because they wear a nice dark uniform with shiny stripes on the sleeve that all students should keep out of their way, be (occasionally) seen but not heard, and not inconvenience anyone higher up the food chain by disturbing their calculations of their stock portfolio.