this whole "on your left" thing seems to work nicely USUALLY as far as other bikers are concerned. but for the general public, it appears to be some sort of secret code for "do a stupid little panicky shuffle/dance with your feet and proceed to your left, directly in path of bike."
three near misses today, one crash. the crash with an apparently mentally-deficient biker. "hello! this doesn't mean 'turn your head and steer bike into oncoming biker.'"