This is me personally and only me.
I am usually quite glad when someone shows up where I am hunting.
I am at the point in my life where I say its no big deal if they want to hit the monster,
or share the spawn, or take it over if that's how they wanna roll.
I usually try to strike up a friendly conversation when they arrive.
If I get the vibe that they want the spawn for themselves, then i recall out and go do
another one or do something else all together. No one person owns a spawn,
So, I do not consider it harassment. I can handle things like that in my own way without
any hard feelings toward anyone.
If I am the one that recalls in and find them there, I will say hello, or how is it going.
Most times they will converse with me, other times if they ignore me, I just go somewhere
else.
Now, that being said: If they are intentionally following you around cussing you and are dragging
half a dungeon spawn down on top of you every time they see you, then I would call
that a harassing act.