Totally agree. I think there could be better signage at trail centres. Most of the downhill tracks I have been to have very clear signs, instructing you that it may well result in serious injury if you're to step foot on it. I'm pretty sure that will keep your average rambler at bay.Perhaps that could be expanded to include some of the faster descents on red and black routes around trail centres? Certainly there could be more clarity on routes...there's been times when I've struggled to find my way, nevermind to know what bits to keep off when you're adjoining from one of a multitude of adjoining public footpaths...
Be careful what you wish for. If the landowners perceive there is a problem of conflict between different users, the easiest solution for them isn't to improve signage.