I’m sure there’s a wealth of experience to be shared on this and it probably deserves a topic of its own.
In my experience I’ve never had a landowner or tenant farmer be rude to me once he knew what I was doing. For the few times a farmer has bothered to come up and talk to me we had a long chat on local history, etc. I think most are bothered about people lighting fires and leaving messes for the farmer to clear up.
I would definitely go to the trig point / summit to activate. Most reasonable landowners, once you explain you’re there only for an hour or so and will leave nothing behind, will be content to let you stay.
As for asking prior permission, it can be devilishly difficult to determine who the landowner is. So [unless you know it’s government / military land] go ahead and activate. If approached, be polite - the worse than can happen is you will be told to leave.
Okay, okay, I’ll create a new topic.,