Originally Posted by
Twin Wasp
Correct, typo on my part, I meant to say *no* RWSL on the 4's.
That is the systemic issue IMO. We can't rely on single-points of failure for runway incursions, either pilot or controller (since the FO may be heads down or talking to the cabin, ops, etc you can't rely on pilot redundancy at all times). I've personally experienced both controller and pilot errors related to runway incursions, and one of them was close. RWSLs provide an extra layer of defense.