Because that
is cheating. 3rd person cam allows you look behind walls/corners, even through buildings and into lower/higher floors
Attached is a screenshot showing how someone in the top of bunker on Omaha can look a floor below him, and know exactly when and how many enemies are coming.
This alone is enough to be considered a bannable cheat/exploit, yet the game provides it at the convinience of a button press.
While for vehicles, it may be necessary to use external cams in order to navigate, for infantry, there is
absolutely no reason for this to be enabled.
And to add to this, you suggest to use the Fly-by view for infantry as well? Are you nuts? Someone can go to the enemy flag, enable the Fly-by camera there, and then walk back into safety of his own base accross the whole map (using minimap to navigate). And the camera will stay positioned at the enemy flag while the player is across the whole map!! He can relay all the enemy movements, vehicles, everything from that flag, to his team.
FH needs to remove external cameras for infantry ASAP!
There is movie-making-mod, that's where all those cameras should be, not in the game-mod