Well, they succeeded, right? Didn't hit the people trying to signal.

But, we don't necessarily know the circumstances - perhaps they had some sort of VIP or other issue going on that would distract them. Ideally, you're right - bridge should keep their 'eyes on the road' so to speak. But really, given how much water there is and how boring that horizon has to get, I can't imagine someone has eyes outboard every second of the day.