Wiggy,
"Certainly when departing from 22R, full'ish length, heavy, you can possibly end up approaching the 31R intersection before the RAAS groundspeed inhibit kicks in...so at around 60-70 knots and just as you're hopefully about to call "power set" you can get a "approaching runway 31 Right" RAAS call....... I've had that gem personally on two or three occasions in a 777-300. "
That sounds like another highly plausible scenario.
I personally really like having RAAS, others not so much because of the nuisance alerts.
I remember one occasion approaching Runway 25 at Twin Falls, Idaho and the RAAS authoritively announced "Approaching runway 26!"
A brief moment of "Uh-oh" in the cockpit followed by re-checking the localizer frequencies and confirming the correct airport on the map display confirmed we were lined up with the correct runway and airport. Found out later that the runway had been recently re-designated 25 due to magnetic correction.