http://www.imafanz.com/Rotator/teststand.htm he has some vids on youtube too trying to seel this crap, dangerous to the max in my opinion, a 90 at full speed held down by the skids? NUTS
He could be checking the gyro direction, blade tracking or even breaking the engine-in? I wouldn't ever use one but I'm not going to shoot it down becouse it's unsafe becouse I dont think it is!
You are never gonna convince him that his product is unsafe. Someone will have to get hurt or worse before he starts thinking "Say, maybe this wasn't such a good idea."
"Some problems don't have solutions, only outcomes" --Isaac Asimov
Thats an expensive box. I believe I can make my own for about 20$ from wood and a swivel from the hardware store if I needed one of these things which I don't.