In reply to
> I'd agree that VBL socks are not necessary for all routes (esp in the UK), but on very long multi day winter climbs you can often end up having very extended days, say from 4am till late into the night, where socks will provide much more warmth when kept dry (after a long day in double boots on a big multi day climb, in the dark, your feet will be much more exposed).
Or, just don't do such scary climbs that make you sweat so much?
I've also got some of these RBH socks http://tinyurl.com/ln543dy
that you've no doubt seen. They used to do a thinner one as well, which I found a bit more versatile. They were certainly warm, but also felt quite clammy, which was more annoying than I thought it would be.
I'm sure though that, as you say, if you were on a long, hard, cold climb where you were standing around in the dark a bit as well, then they'd probably add a measure of safety and comfort. Also, the very warm boots I mentioned above are not good for all things and as you point out, it's actually in trying to extend the range of single boots that I've tried VBLs (not on Denali though).