Onset warning signs, especially in a lighter helo, I'll concede it's not really insane. I don't think it's strictly necessary however.
I'm not in a position to disagree with anyone on here, but I can say that it (incipient VRS) happened to me for real, not as practice. An R44, a bit below gross (three people, half fuel), warm but not hot day, HOGE at 1000 MSL. It was taking noticeably more power than in other R44s I've flown and I'm pretty sure something must somehow be set up wrong on that particular aircraft (though it does have glass panel and pop-out floats).
Anyway... the point is that given the training that I did receive, and seeing where the power was, I was spring-loaded for it to happen, so when it did, no big deal. But we were nearly 200 feet lower afterwards, so it might have been a bit more serious if we'd been at 190 feet instead of 1000.
Practising fully developed VRS would be another matter. It's a bit like practising 6 turn spins. Can be interesting and even fun, but has nothing to do with basic flying skills (imo).