"Look at the number of people who ride the trail centres then try some natural stuff and fail as it wasn't marked with a warning or didn't have arrows to tell them which way to go (or had chicken options) -"
Go on, show us the numbers then.
I think this is basically a daft idea but it's got **** all to do with "nanny state" or "free thinking and choice". Just that it's impractical. If it wasn't so impractical I'd say go for it, not for the riders but for the emergency services and rangers that have to deal with "I think we're somewhere on the red route, maybe not, we didn't bring a map…".
Now, what IS a good idea is what they do at Kielder, every trail section's got a board up saying exactly where you are, grid ref, nearest reliable mobile phone coverage… So in the event you come across a real emergency, you can get help for yourself or others more effectively. No doubt the "nanny state zomg" people object to that as well but it's a minimal investment thing that makes things easier for the emergency services, I can't see a downside. If you applied that to places with really s****y mapping and waypointing, like Fort William frinstance, it could be of real benefit to people- and not just riders obviously but emergency services.