The stock numbers I've always read and was taught were IAS < 40 (and in some machines, like the B206, IAS is unreliable below 40), VSI > -800fpm. I suspect that those numbers don't get one INTO VRS, but reduce the margin of safety to the point that it's a lot easier to get into VRS from that point. Nick, of course you're correct that there will be a loss of precision in static system, but even ignoring your stomach in your throat I think it will still be fairly apparent from the instruments that the machine's entering a pretty hefty rate of descent.
My experience is that interaction with such things as cliffs, ship's smokestacks and stack gas and/or other obstructions can change downwash patterns to such an extent that loss of lift can occur startlingly quickly. Whether any of that is actually VRS is probably not too important, but what is important is to predetermine how you're going to get out of it should you find yourself in it.
Outwest... a fellow I once flew with got into VRS once and tried to get into it a second time in one day while trying to descend to a SAR target with a substantial tailwind. I got us out both times precisely because he was rushing himself, target fixating and busily doing what you recommend rather than fly the machine... I would say my response was perhaps more appropriate. Ball's in your court, mate.