I use a bell.... if I get no response then I keep using it and if still no response I'll slow down to pass at a reasonable speed. Last thing I want is someone to move into my path and have an accident while out doing something I enjoy like riding a bike

When on my own I always stay to the right... and those that pass without any warning do piss me off because what if I swerved due to a bad spot in the path or fallen branch? Those morons don't think ahead. Sure I may be riding in a predictable manner, but predictability is not absolute.

It's rare that I ever do get passed on the trail... but it seems most of the time it happens there's no warning.

"On your left" does make me think I need to move to my left... "I'm passing on your left" would let me know to not move over into that lane. I have a mirror now as well... but no guarantee I'll be focusing on it alot while on the trail. It's better for picking up cars approaching than skinny cyclist.