This is why I have a bell on my bicycle, and ring it any time I have a shadow of an excuse. (I recommend spending a few dollars extra and getting a nice bell that you like the sound of.)
This is a situation where bikes don't necessarily have right-of-way under the law. If there's a bike lane, then yes - and in that case there really should be traffic markings to make it clear to motorists that the right turn lane is on the other side of the lane.
But if not, then bikes are using the same lane as every other vehicle on the road. So when cyclists pass waiting cars on the right at a stoplight, it's just as dangerous and illegal as if a motorcyclist or scooter rider were to do it.
In all cases, motorists needs to be aware of the more vulnerable road users and cyclists should take more precautions when sharing the road with 2+ ton vehicles.
From a cycling commuter for the past 5 years, 37km one way, in the Tokyo Japan area.
* On further thought, maybe that choice of word is inappropriate.
http://deltacycle.com/airzound-horn
Heck, I'd appreciate having a version for pedestrian use, too, sometimes.