I ride multi use trails in my New Mexico town all the time. Signs went up a few years back, prohibiting anything at all with a motor.
Absolutely nobody minds, because I don't ride those trails like a jackass. Many years ago, I did have issues with a few people. They were the jackasses, always insisting that all bikes should not be on the trail, and wanting to walk 3 or 4 abreast. I'd pass them slow as hell, but they always got pissed that they had to move aside for 2 seconds. Just three bitches.
Along with the no motor signs, signs went up saying don't cover the whole trail walking 3 abreast. :lol: Most now do walk or run more to the right.
Bottom line, don't piss off the walkers, and cops have much better things to do. One exception, state park chotas, campus cops, and other deputy dog types with nothing better to do. I'm not sure an ebike would fly in some places, like the pacific beach, or venice beach boardwalk crowds. Look for empty sections of trail to ride, where there won't be cops just watching the trail for drunk a holes.