Last weekend I tried it. I get considerably less broken hulls, practically whole. Kernel was broken all right. So far so good.
I added 0.5 liter of cold water to six kg of malt by pouring it slowly while stirring malt continuously. Waited about half an hour, stirring it once in a while. I milled it with roller mill.
Sadly, mashing to negative iodine test took not one hour, but two. OK, after one hour solution was free of starch, but stirring still released more of it, while it normally does not, at that point. After 2 hours solution was starch-free even after stir, but I heated to mash-out really slowly, just to be sure. Total time - 3 hours instead of a bit over one.
Overall efficiency was unchanged, 90% of theoretical maximum, perfectly consistent with my usual results - but it took over twice the time. Can there be causation along with correlation, or can I assume it was just a coincidence?