so can we stop arguing about the small nuances!
Indeed. Pilots could think of this from the other side, having landed on a runway, and being challenged by a person in authority, what would you tell them constituted your permission to land? Aside from an airport which is publicly presented as being "open", you're could to have to
show how you had the land owner's permission. How will you do that?
In 38 years of flying, I have only once been so challenged. I landed on a nice grass runway, from which years earlier, I had flown the 172 based there. Since, the runway had been sold, and made truly private. I was politely asked to not return, and I never have.
If pilots are going to "explore" these opportunities, it would be wise to be well familiar with any insurance limitations which might apply to where you land the plane. Some policies will state runways which are "open" only. You'd not want to have an oops on a closed runway (without very good cause), to then find out that the aircraft insurance will not pay for the damage - or recovery! That is
not a good example of begging forgiveness rather than permission, that answer may be a cold "No"!