Not just a lightweight but also a full rust proof version makes the most sense to me. A knife that's carried close against your body can rust too, we've had this conversation many times. I'm not sure calling it a "Salt" even makes sense, because I think too many people associate that name literally with salt water activities, but I think there's a real value in a rust proof self defense knife. We have the ARK, but being a neck knife meant for the shower is a bit different I guess.
I think the opposite, why would one need his SD pocket knife to be rust proof ? Rust isn't a problem if your knife is intended to defend yourself.
It's a different story if it's a multi-purpose knife, but the more I think of the Yojimbo, the less I imagine someone cutting an apple with it or pull it out in public to open a package.
I guess it doesn't matter if you're ok walking around with a rusted blade and components? Or if the idea of a rusted pivot that hinders the opening action in the heat of an attack is something you're into. I guess you can counter with a maintenance argument, but I'd much rather go a step further and know absolutely for sure that it won't happen. Lots of guys like to carry IWB too, I don't think I'd want a rusty knife in my wasteband any more than I'd want one that has to be coated with some kind of rust prohibitor that close to my skin. Why not just have a rust proof steel and skip all that? It's not like we're asking for a knife that would be impossible to make or insanely expensive.
Plus a rusted blade means a corroded edge which is dull, that's gonna cost you -3 damage, even though the rust offsets that just slightly with a +5 poison effect due to tetanus, but it's easy to have an immunity to tetanus if you had the shot for it so I can't really afford the hit to my DPS.
