The James C. (“Cox”) Kennedy land dispute on Montana’s Ruby River (see Terran Terran’s link above for context) hits pretty close to me. I’ve floated and fished the section of the Ruby through this land since before he purchased it. When he purchased the land, the Montana Stream Access Law protected that right of way, and public access to it. He would have known this when he bought it, of course. Then, in 2004, “no tresspassing” signs and barbed wire/electric fences were erected to block that public access – which was a violation of public law. The dispute ended up in the courts, and the Montana Supreme Court eventually ruled in favor of the public and the Stream Access Law, but it created years of ugly and unnecessary conflict between landowners and the public.
In addition to Kennedy, many “pro-conservation” landowners in Montana are incredibly wealthy. Do they do good things for “conservation”? Of course. They donate a ton of money and time, and yes, they do use their influence to move the needle forward for conservation initiatives. Examples: Charles Schwab, Tom Brokaw, Huey Lewis, James Kennedy, Ted Turner, Greg Gianforte, the list is much, much longer than this.
All of the above-named landowners own publicly accessible waterways, all of which I’ve accessed numerous times, with varying degrees of conflict on each of these properties. There are remote security cameras, professional (armed) security teams, rough-around-the-edges ranch hands who haven’t really been to diplomacy school. All of them have had a reputation (if not documented evidence) to keep the public out, because they (generally) believe that public access to waterways that have long been recognized as part of the public trust in Montana is unconstitutional and a violation of landowners’ rights and a dilution of their property value.
However… conservation and public lands access advocacy are not the same thing. Many wealthy conservationists believe that the privatization of public lands is the best means towards an idealized version of conservation. Turner et al. are well known to have this view.
Can someone be pro-conservation and anti-right-to-access even when that right is granted?
Yes, and that’s what makes all this so messy, complicated, and painful for the public. What undermines public trust is that most wealthy landowners are unwilling to engage the public in a transparent, collaborative, and respectful way. Erecting electric fences and hiding barbed wire across rivers to rip inflatable boats (a wanton tactic on public-access waterways running through private land in Montana) makes commoners feel disrespected when they are exercising rights legally granted.
Instead, they will exercise their influence through means not available to most commoners, whether legal or political.
Enjoying my rights as a Montanan in 2011 during a packraft float on a public right-of-way through one of the property owners’ lands mentioned earlier:

And FWIW, you need a fairly hefty pair of wire cutters to get through barbed wire efficiently. The Felco CDO is about 9 oz.