Several people have shared their first hand observations already, but the real question is what is the plan to correct it?
In my humble experience and opinion, this is a good example of when catching the last one, there’s great value making the best blind sets that you can. When I’ve been after problematic beaver, I chose to make fewer, better sets. If I wanted to use 330s, I’d use dog down, T triggers which leave half of the jaw space clear so that an approaching beaver seemed to have a clear passage. Secondly, I’d look for the tight spaces that they were already frequently using. “Submerge your traps” is a common phrase, but I believe if legal, blending is more important than submerging. If the trail went through aquatic vegetation, I’d set the either half submerged (and appearing completely open) or submerged trap in place then use the same type of vegetation or woody cover from that location to make the trap disappear. If you can submerge AND blend in a tight space that they travel, that’s a wrap.
No exposed trigger wires, or at a bare minimum, vertical trigger wires pushed to the side to give the illusion of a clear space to pass then make it look like nothing is there. To do this means taking advantage of the best locations—-not building a fencing fortress where it doesn’t belong. It’s their world, and major (sometimes even minor) changes can complicate the situation.
Snares are a fantastic tool for catching beavers, and so are well placed footholds. If someone is trying to catch “some” beavers, they can get away with a lot more as catching “a” beaver is easy. I do believe a person is better off making the highest quality sets they can when they’re trying to catch the “last” one on a regular basis. Sometimes even the last one is easy, but when it isn’t, it pays to do it right from the start.