I am not sure this is doing what you think it is.
Currently those hunting with non-modern firearms may NOT carry a modern firearm during the archery or muzzleloader season. This is not a Title 9 violation, but it is part of the game code, just as the law regarding loaded long guns in vehicle is a game code issue.
This is a step in the right direction, if you ask me.
Also, it is part of the WAC, as far as I know.(b) It is illegal to carry or have in possession any firearm while in the field archery hunting, during the archery season specified for that area.