I find it endlessly fascinating how people can have very different reactions to similar situations (why I love Reddit!). We had a riding trail that continued on from our land to a neighbor's land. We used it for decades. It was eventually sold and the new owners posted the land. It never once occurred to me to continue using the land. New owners, new rules.

RE #2: I would never expect people to ask each and every time! That is crazy. Annually was always the norm and that would be just fine. These people do not ask at all and the few that I have confronted (kindly and politely) have stood me down on their "right" to continue using our property. I've never said that they can't be on the land, I've just asked that they hug the tree line so that we have more privacy. I can't begin to fathom responding that way to a request from a land owner. If I was on someone else's property and they asked me to leave or use a different route, I would apologize profusely and NEVER go where they asked me to avoid. Frankly, I would never be on someone else's land without explicit permission. We need to cut through a neighbors property for some maintenance issues and they have told us to go any time. I still ask when we are about to do a big project. It's just basic common courtesy.