In all seriousness, signs like this are fairly common in my area, many saying "Steep Hill - walk bikes". They're not intended for serious cyclists, but for newbies, children and relatively inexperienced riders who often more speed than they can handle.

Steep descents remain a major cause of accidents. I remember many years of riding TOSRV, and later volunteering. After a few years, the National Guard, who provided medics and emergency transport knew exactly where accidents would happen. Among the places was a short steep descent with a curve. The crew stationed there had a dream of so perfectly placing the ambulance that they could catch a crashing rider on the fly. Of course that never happened, but they did have crashers come to rest within a few yards, which saved some walking.