Much like (and if you'll pardon the Trek reference) the Klingons who switch to swords and bat'leths when attacking a battle station populated by soldiers with energy weapons, the tactic of turning off your saber or avoiding attacking an armed opponent to show "honor" is foolish, and if you get killed doing it... guess what.. you deserve to lose!
(the above example btw, is well known in the Trek community. What some see as the epitome of honor, military strategists see for what it is, a foolish, borderline suicidal gesture!).
If somebody has their saber selected, but turned off, they are STILL DANGEROUS. They can still not only attack with the force and use items (unless it's during a saber challenge), but the instant they press the "attack" button their saber will spring to life ready to strike.
So IMHO, to give a person with their saber turned off some kind of protection by not attacking them, is to effectively give them a "free hit" on you.
By the same token, to turn off your saber, and expect others NOT to attack you is foolish. You might as well keep your blade out, and at the ready. After all, the auto-blocking powers of the saber are ZERO when your saber is turned off, and so somebody could easily snipe you and do full damage.
If you're smart, you'll never underestimate somebody with your saber off, and you won't turn your saber off and expect people to stay away from you.*
Notions of honor have a place in Role Playing Games about honor, not in a First Person Shooter, or in a competative multiplayer contest. People may disagree, but that's the way it is, unless the server admin wants to shoe-horn his players into that mould. That's fine, but it's a set of handicaps that players have to willingly accept, it can't be forced on anyone.
To avoid falling victim to "jerks" who don't follow the honor codes you do, simply stay on your toes, type only when you're dead or in spectator mode, and don't whine when you do get caught "off guard."
* Unless of course the rules of the server you joined explicitly state that you are to follow these so-called "honorable protocols." I just assume that they are NOT default on most game servers.