It is a bad idea all around unless you are planning on engineering a rerouting of the waterway. Those pathways were cut into the sand and stone by rushing water in the past, dumping sediment even if one takes the time to try to mimic compaction is just a temporary fix. The homeowner would need to add new sediment and/or a concrete reinforcement (ala a sea wall style) to make it hold out longer. It is just more reasonable to not build there unless one is really intent on it and has significant resources to pull it off. As a camp, you are exactly right, there is just too much at risk and it would take some expensive engineering to mitigate it further.
I knew nothing about this place before. But I know enough to be able to evaluate locations based on just looking at the geology/geomorphology even though this is not at all my area of expertise. Someone with much more credibility (any hydrologists on here?) could better advise and plan this out.
I imagine the camps don't start out flush with cash and their ignorance of history beyond their lifetime or local only knowledge is not a sufficient excuse. Harry Truman of Mt. St. Helens could testify to that if he wasn't erased from existence.