RF is Radio frequency, and it's used to automatically read your lift pass as you go through the gate. My home mountain (Okemo) doesn't have it in place. They still use the old eye-ball technique -- which is far less annoying (and probably less effective) than the scanners they use at some areas, where they use hand held gun scanners to read your pass every blasted time you go for the lift (I hate that). Still, RF seems more common in the west than it is in the east.
Does your mountain use RF?
Does your mountain use RF?