It can come down to individual pathways being under city or town law, or private rules like on a college campus that is private property.
To see about the larger picture, look up your motor vehicle laws for the province.
Then ignore it all, and ride like a gentleman, and you can likely use the trails. If you look like a regular bike, that is.
That's the way it works for me. All the multi use trails posted no motors. I ride them all the time and cops just ignore me when I'm seen. A few stupid people have confronted me, but never law enforcement. Those confronting me objected to ALL bicycles btw.