The Haworth Mudman Duathlon, unfortunately now defunct,bike section ran mainly on bridleways, the Kielder offroad Duathlon, the Coed Y Brenin Duathlon, the timed sections of the Trans Wales at Nant Yr Arian and , I think, in the Dyfi forest. All these events are races timed to the second and awarding prizes for winners etc, and these are just the ones I’ve either done or know the course of. I’m not trying to be a killjoy but often the organisers don’t know the law themselves.
I think my comment about racing numbers cannot be disregarded, competitors in such events will not just be pootling along in ones and twos and someone being injured by a rider with a number on will not necessarily care whether they were on a timed section or not. They see a race number, they will think there is a race going on.
BTW anyone know how the organisers of the Llandegla Duathlon or the British Cycling Go Race or Firemans Race deal with the bridleway that runs straight through the middle of the bike course?