11.08.2014, 00:39
The answer is GetVehicleVelocity 
Hope it helped, here it is in the wiki CLICK HERE
Edit: Oh, sorry, I didn't see you meant if a player falls from Mountain Chilliad.
But, I think I have an advice, not sure if it'll work.
Try to get a player's range and check if he's within mountain chilliad and like maybe 100? meters away from.
And if they are just make the variable of the anti cheat not work there.
I guess this could work if you think about.
Edit2: Actually, I have another idea, you said there were alot of places people can do that and fall from above, so I assume you have a DM/stunts server.
Then why don't you set the variable of the anti cheat to false once a player teleports to that location.
And then check when vehicle damage has been dealt to the vehicle meaning it has fallen from above or something.
Then turn the anti cheat on.
Hope it helped, here it is in the wiki CLICK HERE
Edit: Oh, sorry, I didn't see you meant if a player falls from Mountain Chilliad.
But, I think I have an advice, not sure if it'll work.
Try to get a player's range and check if he's within mountain chilliad and like maybe 100? meters away from.
And if they are just make the variable of the anti cheat not work there.
I guess this could work if you think about.
Edit2: Actually, I have another idea, you said there were alot of places people can do that and fall from above, so I assume you have a DM/stunts server.
Then why don't you set the variable of the anti cheat to false once a player teleports to that location.
And then check when vehicle damage has been dealt to the vehicle meaning it has fallen from above or something.
Then turn the anti cheat on.