Something just occurred to me. I have never, ever, in my entire life, seen a "Men Working" or "Crew Working" sign. Maybe this is a Canadian thing. Isn't it evident by all the traffic cones, reflective vests, cement mixers, power tools, caution tape, excavation devices, noise, swearing, hard hats, dust, empty coffee cups, and cigarettes, that you are near a work site? Does the US have an epidemic of idiots falling into holes whenever a little orange sign isn't present? Should we really miss these people enough to try to warn them?
Let's approach this from another angle. Instead of changing the sign, why not get rid of it all together?