Like you George, I wanted to be legal on the multi-use paths, so I studied Oregon's laws which clearly state that a "legal" e=bike is considered a bicycle and not a motor vehicle. So that means, in Oregon, the no "Motor" vehicles signs can be ignored.
However, cities, state parks, etc. have the right to ban e=bikes from their paths, by statute. This was the case in Eugene, Oregon until about a year ago, and the signs on their paths said no "Motorized" vehicles instead of no "Motor" vehicles.
I also rode my e-bikes on paths in California, ignoring the no "Motor" vehicles signs, thinking that didn't apply to me. I've recently learned that California law didn't have a special classification for e-bikes and they were considered motor vehicles and thus not legal on their paths. This is currently under revision in California.
So apparently it all depends on the state laws and the local statutes and ordinances as to whether a "legal" e-bike can be used on multi-use paths. My current attitude is ignorance when riding in other states, since I always ride at a reasonable speed and normally pedal. Sort of like making a right turn (when driving a car) at a standard intersection when the light is red. Legal in Oregon, after stopping and when there is no pedestrian or cross-traffic, but not legal in Nevada (at least it wasn't last time I checked). Never was stopped, but always just planned to plead ignorance and pay a fine if necessary.
Last year I drove from Oregon to Kentucky and back and certainly didn't compare all state laws to Oregon's. I feel the same way about the e-bike laws, and whether the sign on the bicycle path says no "Motor" vehicles or no "Motorized" vehicles I will continue to ignore it.