Lancelot
Adventurer
I stick fairly close to the rules for the players, because they have expectations as to their capabilities. They also have expectations that monsters are adhering to the same fundamental rules of combat that they are. So, a charging monster can't act after the charge unless it uses an action point... it needs to use a standard action to second wind... etc.
However, I'll cheat behind the scenes if it helps create good dramatic tension. A hit which "should" have killed an ogre might leave him with a couple of hp so he gets off a final attack... a fire giant might have an attack power that lets him pick up a PC and throw him 30 feet with a single hit roll... and a skill challenge DC might very wildly depending on how impressed I am with a PC's suggestion.
The challenge for me as a DM is that we have a long-standing convention in my group that all dice are rolled in the open. This means that we have a social contract that we accept the potential for high casualties, with few DM "saves". If the players see that a monster hits on a roll of 14 in one round, they're not going to accept that it misses with a roll of 17 in the following round. The reverse is also true.
So that limits my ability to cheat to things that can't be visually confirmed. 4e monster powers are a perfect example. Because they don't operate under the same assumptions as PCs, 4e monsters can do virtually anything. To paraphrase another thread on EN World, I wouldn't worry about the rules behind "trapdoor bugbears". If I want a creature to be able to spring out of hiding, grab a PC (with a hit roll), drag him back 3 squares, and close a trapdoor behind him... he does that. That's what his power does. The players can't confirm that he can't do that, because they know that "monsters are different" (...and besides, there are plenty of similar examples in the MM and MM2).
However, I'll cheat behind the scenes if it helps create good dramatic tension. A hit which "should" have killed an ogre might leave him with a couple of hp so he gets off a final attack... a fire giant might have an attack power that lets him pick up a PC and throw him 30 feet with a single hit roll... and a skill challenge DC might very wildly depending on how impressed I am with a PC's suggestion.
The challenge for me as a DM is that we have a long-standing convention in my group that all dice are rolled in the open. This means that we have a social contract that we accept the potential for high casualties, with few DM "saves". If the players see that a monster hits on a roll of 14 in one round, they're not going to accept that it misses with a roll of 17 in the following round. The reverse is also true.
So that limits my ability to cheat to things that can't be visually confirmed. 4e monster powers are a perfect example. Because they don't operate under the same assumptions as PCs, 4e monsters can do virtually anything. To paraphrase another thread on EN World, I wouldn't worry about the rules behind "trapdoor bugbears". If I want a creature to be able to spring out of hiding, grab a PC (with a hit roll), drag him back 3 squares, and close a trapdoor behind him... he does that. That's what his power does. The players can't confirm that he can't do that, because they know that "monsters are different" (...and besides, there are plenty of similar examples in the MM and MM2).