I AGREE that student pilots should be allowed to do a "a practice PAN call" BUT not on guard frequency!
They need to practice what to do if they get lost, and they can get a fix from ATC on an normal frequency.
If that frequency is too busy to do it on, of course ATC has a backup frequency to escort the guy.
Let's keep guard frequencies open for what they are intended for: emergencies only
That way, my volume isn't turned down (because of a practice PAN) when i really need 121,5.