I don't hassle with bike trails where I live under power. For one thing they're too crowded, slow bikers, families with kids, people on foot. Where they cross roads there is always people walking dogs. If I do ride a stretch it's to connect with another road and I shut the motor off.They'll need to post the trail "No motor bicycles" to get my attention. No motor vehicles just means I can't drive my work truck down the trail.
They're posted here no motor vehicles. If MBs ever get popular enough to become a problem that warrants a separate No Motor Bicycles Allowed sign, I think it'll mean the time of being under the radar is over and it won't stop there.