I demonstrate the inital stages of dynamic rollover, ie purposely put the stick off centre before lifting off and point out to the student that one skid lifts up, and they should reduce lever and try again.
Frank said at the factory course (or in the safety the video, can't remember which) that it is not possible to get the R22 into retreating blade stall.
I still think it's important to demo initial VRS and how to get out of it as it's a lot easier/more common than jack stall/twin engine failure/retreating blade stall.
A pilot can easily fall into VRS, eg when taking friends/photographer for a ride, 'oh look there's my house, can you slow down? just a bit more, that's it, great, hover here, eh? what's happening, sh*t!' etc etc.