Start a guildwar then.
This is different.
KohnBosk's suggestion is an excellent one to solve another type of issue. Let me set the context - this is what actually happened.
Eila was crafting peacefully at the cursed anvil by harnquist's when she hears a body hit the ground.
She turns to realize that a defenseless, clueless newcomer has been struck down.
Perhaps because the new-comer didn't know any better? A moment of inattention? Regardless...
The hereby-unnamed coward who did the deed was challenged (and refused, again, it wasn't the first time).
He nonetheless walks away calmly with not much more than a warning and a few insults thrown at him.
His only response to our RP was "give me a break!".
( A few instants later Laanx did strike him down - nice touch, but... )
For the sake of RP, when a situation like this arises, i would have wellcomed a system that allowed me to engage him.
A timer triggered at end of his duel with his victim would solve this issue.
Eila