I will do this on occasion when I shave with a tallow soap. I am a face latherer, and I usually do a warm water rinse between passes to give a little extra moisture for the next lathering pass. I started to notice that my face was quite slick if I didn't totally scrub the soap off, so I gave it a shot, and heck, it works!
I'm mainly a Gem-style SE shaver, though. I think I'd have to get my SS skills pretty darn dialed before I'd try a pass with little protection.
[COLOR="red"]GEMOCRAT[/COLOR] [COLOR="blue"]4 LYFE[/COLOR]
[COLOR="black"](still thinking up a good gang sign)[/COLOR]