Hi there.
Rotor brakes are fitted to slow the rotors down. I simple tie down is all that is required to keep the rotors still when not moving. The Blades rely heavyly on Centrifugal force to keep them up and away from the tail boom and above passengers heads when under the disk. As the blades slow down there is very little control lift to keep them where you want them so the idea is to take them from the lower control speed to stationary as quickly as possible.
I saw that clip as well and it did look quite harsh but if you really knew what is happening to those blades during flight you would understand that it is not actually that bad.
I fly aircraft with and without rotor brakes and i know which one i would prefer to be in when shutting down on a windy day.
Hope this helps
HB 999