[4e] I'm helpless!

[Burley]

Well, not really. But, that's my problem.

Anyways, it seems to me that the only way to Coup de Grace is for an enemy to be helpless, and the only I can see to do that is for them to be unconscious. And, the only way I can see to do that without them being "dead" anways is the Wizard power Sleep (level 1 daily) and then, it's only 20.25% of that actually happening if you hit.

Any other ways?

[Totally Guy]

Although I've seen my player's use it, it was not in battle, an antagonist has tried it against a PC in battle though.

When you attack an enemy you can decide whether to use lethal force or whether to simply subdue your opponent.

Coup de gras allows you to kill your prisoners without having to roll to hit. Which has happened several times.

[Tengu_temp]

I don't see this as a problem. Removing most of the "hit them with a save-or-lose, CDG, lol" tricks is intended design for fourth edition. These rules are mostly for figuring out what exactly happens if you sneak up on a sleeping ogre and decide to slit its throat.

[Kurald Galain]

Coup de gras allows you to kill your prisoners without having to roll to hit. Which has happened several times.
No, it doesn't. You need to roll to hit for a CDG, then need to roll again for damage (assuming you have one of the various common things that add damage dice on a critical hit) and then the damage has to be enough to kill the target, which is unlikely unless you're a striker, and moreso at higher levels.

However, there's also other powers (e.g. a rogue's Knockout) that cause unconsciousness.

[AgentPaper]

Looking at the rules for helpless and coup-de-grace:

Helpless only means you grant CA, and you can be targeted by a coup-de-grace, nothing else. If somehow you were helpless but no other status, you could still move, attack, flank, etc. Unconscious makes you helpless, as well as preventing you from taking any actions, giving a hefty -5 to all defenses, and preventing you from flanking. (and possibly making you fall prone)

There's never a time when you don't need to roll to hit. If you're asleep ala the Sleep spell, you grant CA and take a -5 to defenses, but you can still miss if you roll bad or they just have a crazy high AC. Coup-de-Grace just makes your hits into critical hits automatically, and if you do equal or more damage with that hit than the enemy's bloodied value, (half their HP) they die.

Of course, if you're executing prisoners, you probably don't need to worry about any of that. This is where the DM just says, "You kill them", and moves on.