[scott_w]

Given how widely known this tree at Sycamore Gap was, you’d have to be the stupidest person alive to accidentally cut it down. There are literally no other trees nearby.

[Archelaos]

Yes. Zero probability. Just look at this pictures from the different sides of the gap:

https://commons.wikimedia.org/wiki/File:Hadrianswall-60-Syca...

https://commons.wikimedia.org/wiki/File:Looking_Southwest_to...