Is there any reason not to always try to knockout rather than damage?

Question

I was re-reading the rules of Call of Cthulhu (5th Edition) today whilst preparing an adventure and saw the knock out rules:

Use this rule to render a target unconscious rather than to do physical harm. The player or keeper should state the intention before making the attack. Perform Knock-out attacks only with Fist, Punch, Kick, Grapple, Head Butt, Clubs or other blunt instruments. Roll for damage as in an ordinary attack, but match the result against the target’s hit points on the Resistance Table. A success knocks the target unconscious for several minutes, and the target takes one third of the damage originally rolled (round down any fraction). If the attack succeeds but the Resistance Table roll does not, then there is no knock out, and the target takes full rolled damage.

As I understand the rule, there isn't any kind of trade off for using this kind of attack: Either you knock out an opponent for several minutes (big advantage because knocked out opponents can't do anything, and several minutes probably means the combat ends before the opponent awakes) or you cause normal damage. Provided the opponent is affected by the knock out (ie not a mythos creature) and you have a blunt weapon, why would you not always go for the knock out attack?

Answer 1

From a mechanical, Rules as written standpoint, there's probably no reason NOT to try this every time. But the Keeper may throw a monkey wrench into your plans. But keep in mind just because you can, doesn't mean that it's an ideal situation all the time. Consider these reasons why it might not always be ideal:

1. You don't know the target's resistance (unless the Keeper automatically gives you that information) and it may be ineffective. Example: trying to KO a boxer vs. someone with a "glass jaw." Even if you DO end up knocking them out, it doesn't mean they won't wake up again, and have to deal with them again. So knock them out again (this isn't the cartoons, where you notice someone waking up and you bonk them on the head again to knock them out). Even though we're dealing with "Standard humans," the Keeper is free to adjust stats and resistances as s/he sees fit.

2. It may be safer to attack the target at "arm's length," depending on the target's training.

3. You may want/need to take the target down "once and for all"

4. You may not have the room to swing the weapon around without alerting others of your presence, and a more lethal weapon may be a better choice.

5. You may be on a timeline and killing may be more efficient than knocking out.

6. What would prevent as you attacked one character to knock them out, more enemies came and did the same thing to the player(s) who did so? If the enemies are even remotely smart, they'll soon pick up on the techniques the players use, and over time be able to "turn the tables" on them.

Answer 2

There technically is no disadvantage in knocking out opponents instead of killing them (since you can coup-de-grace a KO opponent).

However, you can do so only with Bare hands, grapples or blunt weapons. I don't know the 5th edition well, but if it's the same as in the 6th or 7th, these weapons are pretty lame.

The trade is : to do KO damage, you have to use a crappy weapon. Seems fair and logical to me.