If I have student show up with one of these stabilizing training aids on their plane I'll discuss the pros and con's of it so they'll understand why I'm disconnecting it. If they insist on having it hooked up I'll send them off to another instructor as I will not fly with one for many of the same reasons as RCKen pointed out.

When I have a student up on a first flight on a buddy box, they usually don't touch the sticks for the first 5 minutes. I like to demonstrate as much of the capabilities of the plane as possible. One of the last I demonstrate is the recovery capabilities - as much for me to know how their plane will react to releasing the sticks when its in an unusual attitude as for them to see how the plane will react and just dive for the ground. Most properly trimmed and balanced trainers will start to return back to level flight and if given enough altitude and distance will. But in reality releasing the sticks will allow the plane to more or less turn upright and get into a position more recognizable for a student to make the proper corrections to recover the plane.

Hogflyer