@Spectre. Those are good points you make, but I would ask two further questions:
--In your training with a bow, have you also been trained to hit people on the wrist and poke them in the eyes with it? Are you as proficient doing that with a longbow as someone who has trained with a bo staff would be at parrying melee attacks? Or would you be less effective at it than someone who has trained to use an actual melee weapon as a melee weapon?
Those are two examples of what parrying could be regardless of what is held in the defender's hand. A bow, a bo, a pool cue, a broken chair leg... the item can be used to parry at the attacker's hand, wrist, arm, elbow, face, neck, etc. the main point is that "parrying" does not mean "weapon vs. weapon contact only." Parrying can be many things.
I have zero bow training. I tried it at a young age and didn't have a wrist guard and after a few whacks of the bow string on my forearm, I quickly lost interest. When I was older, I wanted to try bow hunting. I found I can't draw a compound bow at all. 50lb pull and 35lb hold? Can't do it. But I would still rather have that bow in my hand to defend myself than nothing at all, even if I have zero bow skill.
2nd question is a little unfair and tricky to answer. Having trained with 6' staff, there is little to no difference with a 4' staff (roughly long bow length and standard bow lengths) Knowing how to use a length of wood between 4' - 6' regardless of it's name or function, is no different. In that sense, it's not a fair question because the trained weapon user is just using a tool as an extension of his body. The same person can use a sword probably more effectively and in fact, training swords are often made out of wood which is just a fancy looking club at that point (or table leg or stick or lead pipe... who finds lead pipes laying around??? Ever???). Legolas used an arrow like a dagger to stab an orc in the eye. That should have carried major penalties for not being trained in 1H Thrusting Weapons and using improvised weapon and using the arrow in a manner in which it wasn't intended. That bow-elf held his own in melee with a bow.
In the spirit of the thread topic, obviously I have to say "most likely not" but not a definite "no." Just because the bow user wasn't trained specifically to beat an attacker with the bow but it doesn't mean he doesn't know it can be used as a deterrent in a fix. Definitely not habit he wold want to get used to. However, as the bow user advances in skill and is more comfortable with it and far more familiar with it's weight, length, balance point, etc. he could be effective at knowing how best to protect the bow string and jab at an attacker's face to distract him. The purpose of the parry is to detract from the attacker's ability to make a full OB attack. Poking at the face really isn't a trained combat skill at all as much as it's an innate self-preservation survival reaction that even animals use. Go for the eyes!!! (Or the groin) I'm sure if I backed PeterR with his bow into a corner and I'm attacking him, he's going to kick at my groin, try to hit me in the groin with his bow, or maybe lunge at my face with the bow, anything to break my ability to get a clean solid shot at him. Peter is going to use the bow to aid in defending himself as opposed to using only his empty hand to defend himself in a desperate moment.
I can hear his battle cry now "Not in the bow! Not in the bow!"
* I chose PeterR because we have a fun, working relationship, not because I want to attack him with a sword. Sorry Peter, no ill-will intended!
--What happens if you don't have a pillar to run behind or a chair to throw in the way of the attacker? In fact, Rolemaster does not have any movement requirements at all: you can be caught completely still in a corner, with literally nowhere to move, and still not suffer any penalty for 'parrying' with a longbow.
RMC at least addresses this issue somewhat by making a 2-handed parry less effective: characters can only parry at 50%. But this produces a rather strange result if we consider that one could parry with a sling (one-handed to shoot) presumably full OB? If so, the game is kind of saying that you are much better off parrying with a sling than with a longbow.
First question, again, just examples of narrative explanations that could be considered part of parrying and getting out of the way of the attack. All these fluid variables can be used in narrative to explain why the swordsman didn't hit the bowman as effectively as he wanted to.
In my previous post, I forgot the 2H Parry Rule. RM2 has the same rule: 2H weapons parry at 50% max. In real life application, I don't understand that, but for game play balance I understand it. No shield = 50% of your defending ability... or power balance as 2H weapons deal out much higher damage. I understand it for game play and our players don't have issues with it. So my example of the bowman with 150 OB should only be parrying at 75 OB max, but he's also going against attacker with about the same OB so he's still at a marked disadvantage. And to get to 150 OB he's arguably level 15+ PC? (10 ranks at 5%, 10 ranks at 2%, 10 ranks at 1% = 80 OB before stats and bonuses) By level 15, having fought many goblins, demons, vampires, maybe a dragon or two, and countless BBEG's, the bowman must have picked up a thing or two from his melee companions and knows how to best utilize that 4' - 6' stick in his hands in a desperate moment.
Bow parry and sling parry. I hadn't noticed that! Good point. You can argue the sling is 2H because you need to hold the bullets with one hand and the sling with the other??
That is definitely not a fair game feature. Although maybe you can snap the sling like a wet towel? I would still rather have the bow to parry with than a little strip of leather.
Just for very basic, most simplistic means of self preservation, any human being with no weapons skill at all, no bow skill at all, can take a stick or a broom or a shovel and just jab and swing wildly at an attacker to try to deter the attacker. You see it in security camera videos (my wife watches Caught on Cam on Netflix all the time) a person grabs whatever he can find to try to fend off an attacker and just jabs, swings, pokes wildly. A level 15+ PC should be able to do the same with more aplomb and more calm, cool, and collected in a battle than the poor bloke being jumped for his watch and wallet.
I'm tellin ya, a stick poking at your eyes is a good deterrent!