I'm pretty sure the GMs have gone on record saying that even resetting a hunt isn't necessarily something that can be considered an offense unless the majority of the players present showed that they were bothered by it.

But yeah, those players technically didn't do anything wrong, though it is pretty rude to camp out in a zone and wait for other people to spawn something so you can kill it before them. When I see people trying that I just hold the node and wait for them to leave before I actually gather.