I prefer to keep my folders dry. Prevents accumulation of lint, dust, dirt, ect. Lubrication makes sense for high-friction machine parts, but with teflon or bronze phosferrous washers, I find that my folders open just fine dry. I don't worry about wear, even if I have to open my folders frequently, after all, teflon and bronze phosferrous are pretty slick materials. I also don't need my folders to open "lightening fast".
I would also consider the possibility that a folder with a blade that flys open, super slick and fast, might suffer damage as a result. Liner and frame locks can over-engage, causing premature wear. Stop pins can get hammered.
But don't get me wrong, I'm not saying it's wrong to lube. Your knife, your choice.