Interesting how he gives it a shove and it glides on the wheels to a new position. I'll bet he stops doing that about the time he shoves it and a wheel/caster catches on a small pebble or nut, something on the floor kinda like a shopping cart does. Suddenly the dolly stops but the bike keeps going since it has more mass and it's up high. Over goes the bike. If I were to use something like that in my garage, I'd have a quick hook up with a strap from the left side down to a spot on the dolly. Lessens the chance of the bike going over should the dolly hit something on the floor.
John, I push my ST1300 around from the kickstand side. One hand pushing on handlebar end, the other on the passenger grab rails. Whilst it's leaning over it would take a lot of force to push it past vertical.
I have a less than perfect floor so it certainly doesn't roll like the video

I've read that some have put larger castors on but for my inseam the bike is far enough off the ground.