The death duel invitation had to have the thumbprints of both parties in addition to the thumbprints of two outer court elders.
If the other party accepted the invitation, then it would be a fight to the death!
They could reject it, but it would be perfectly justifiable for the party who sent the death duel invitation to battle them and teach them a lesson. As long as the latter did not kill or cripple them, they could do anything they want.
This was the death duel invitation.
As for the general duel invitation, once it was sent out, the other party must accept it as soon as they see it when they come out of closed-door cultivation.
If one were to refuse, it would be perfectly justifiable for the person who sent the duel invitation to break in and fight even if one was still in closed-door cultivation.
The duel invitation was one of the specialties in the Moon Illumination Sect.
…
The Moon Illumination Sect's entrance exam ended close to evening.