["1stPerLimit", "onEachFrame", {
   if (cameraOn == player && cameraView ==  "External") then 
    { 
      player switchCamera "Internal"; 
    };
}] call BIS_fnc_addStackedEventHandler;

This code prevents player from switching to first person view, but everytime the player presses the the key to change the camera view the display blinks. (See video)

Therefore I request a new command which allows us to disable third person view or force a player into a certain view mode, e.g. force first person view when not in a vehicle.

Example:

disableThirdPersonView [onFoot,inVehicle];