Maybe other people have run into this.  You're fighting a rare spawn, such as the honor-dropping ones in Krasarang Wilds.  You're doing just fine.  Maybe you even have it very low, 5% or less.  Someone flies back and does an invite.

I'm not sure whether to laugh at this or be insulted.

Do they think that I somehow need help?  If I did, I'd get a group.
Do they think I'm stupid enough to let them roll against me when I don't need them?
Do they hope I'll just absent-mindedly click accept?

Whatever it is, they should fuck off.  At the least they shouldn't sigh at me when I refuse the invite.  What's next, demanding half the ore when I get to a node first?