I'm sure I remember being told on a flying safety course that the UK Puma accident mentioned on the previous page was vortex-ring related - obviously there could be a number of explanations depending on how much information the crash investigators had to go on, but it sounded plausible.
As Mighty Gem points out, the quickstop manoeuvre we want to fly starts out downwind and finishes into it, but the story with those guys was apparently late identification of the pad, picking the wind direction wrong leading to a quickstop that terminated effectively downwind, winding up with them falling through and hitting the ground in a scenario fairly close to the conditions I went through above, ie relative airflow into the disc at the right angle and rate to set up VRS.