The guy had no clue about what he was talking about...
That's the Valet switch. Let's see if I can remember how it works - I just always leave mine turned off...
If it's UP, it think that's "alarm off", and if it's DOWN, I think that's "alarm on".
If you press the keyless remote, and it "chirps", the alarm is on.
BY THE WAY, if you have it ON, and you shut the engine off, and close the door, after a short period of time, it WILL lock the doors! My wife discovered this at the car wash with my 4-door - I had to come unlock it for her, because she left the keys in the vehicle.