But remember: your RuneQuest will vary.
To me, it makes perfect sense that two fists does not grant an additional CA. The reason is that unless you're trained in some martial arts, there are several issues to striking with both fists.
If I hit a person with my right fist, I will have to move myself close to him in order to strike properly and I will have to put a lot of weight on my right side (which potentially can throw me off balance if I am not careful). Now, if I would want to strike him with my left fist shortly after I hit him with my right (in rule terms, expend my +1 CA for dual wielding hands) my hand will be too close to him to gain proper momentum, my balance will be off to the right and therefore hinder my ability to strike with the left hand.
Before I can strike him with my left hand, I must regain balance and move away a bit to gain proper momentum (striking from 20 cm away doesn't hurt enough to validate 1D3 damage). In rule terms the potential I had for a +1 CA will be spent on going back half a metre and regaining my posture.
These problems are different in armed combat (they are there! But in my experience one needs to be a pretty good swordsman to take advantage of things like this - something that is already reflected in the combat rules via extra CAs and higher skill level). In armed combat the dagger still hurts even if it only had 10 cm to gain momentum.
If one wants to take things into extreme realism, one could rule that a person can dual wield a free hand and a dagger, as long as the dagger is used by the off hand (else the hand would still not gain enough momentum to strike properly). This could allow for situation where one stealthily draws a dagger in a fist fight, then jams it up the opponents abdomen when locked tight... Cool rule, but something the game designers properly avoided because too many special rules tend to slow down gameplay... But albeit it a possibility.
- Dan