Originally Posted by
CACycling
I only say "on your left" when coming up on people that are blocking my way (taking the whole path, dog on leash, walking on the wrong side, etc) and say it loud enough and far enough back that it usually gets their attention. I make sure I give myself plenty of time to react to whatever move they end up making.
+1
I have found that trying to warn people almost always causes them to swerve INTO you (peds and cyclists). If there is space, I go into stealth mode and pass as quietly and with as little warning as possible. If there is no space, I hit the brakes and start yelling well in advance of my arrival.