Adding Monsters

[Wily]

Can monsters be added to fights that the players knows they can't win for the sake of piling on bad stuff. For example, i was tied with a pair of monsters and knew i was not gonna be able to defeat so i said announced it. Someone decided to add another monster. It might not be prohibited by the rules but it feels very anti-Wheaton's Law. I just wanted other people take on it because it was being argued both way by our group.