Iv'e watched this a few times now, not sure if he camera boat is underway, hard to tell if she's stationary so possibly at anchor.
On the other hand the trip boat is almost certainly underway so has as much if not more to blame for not keeping a proper lookout.
I dont think the skipper off the camera boat would stand a chance at defending his actions if she's underway.
Upon further watching I would have to say I agree with you, I don't think the camera boat is underway at all, maybe not at anchor though just from how it looks... I think if the biggun had been underway then it would have made a greater impact and/or carried on going, it wouldn't be stopped by the one relatively small boat, surely?
I reckon it's a case of no-one at the helm for some reason on the smaller boat...
Not if he's anchored or NUC !
The signals (if he's hoisted any) as you sudgest would be out of shot.
Hard call but if it was underway then I would assume the skipper would have made a drastic change in dirrection or speed none of which is evident from the video clip.
Not sure if its the sandy seabed you can see or cloud reflection in the water, but it certainly appears that the camera boat is under way, albeit slowly.
Remember it'll mostly be seen in silhouette. It's clearer to other boats to have it on the bow, cos there's usually no other clutter there. If it's mounted high up it could be confused with radar / sat tv dome etc.
I've looked at it a few times now and agree that the camera boat seems to be stationary. The only relative movement looks to be the small chop coming across the port bow.
If the larger boat was underway the momentum would either roll or heel the trip boat over or it would slip along the side of the camera boat and out of sight.
I'd say the crew were justified in waving their arms.
Being stationary doesn't mean it's anchored. They may simply have stopped.