What if they were not even in doubt but sure that they will pass by without incident ?
Then you would never have anything about it, because there would have been no collision!
Semaphore is 100% spot on ... if in
any doubt you stop, and that includes any time (certainly in a large aircraft like a B747) when anything transgresses the painted lines. As he says, you career is on the line, any collision is totally indefensible.
ex-B747-400 Captain