Yeah that's fair enough... Most aren't as conscientious as you though. I guess the law exists to account for the lowest common denominator.
Trivia:
Up here we have a quite well developed bike lane system... most are 2m wide and painted in bright f*ckoff green antislip paint.
But that's mostly due the prevalence of Japanese people here on work visas... (thousands...)
In Japan bikes rule supreme (They outnumber cars by about 7 trillion:1) ... and have no real rules attached to where and how you should ride them.
So they come over here, pick up a cheap pair of wheels, and proceed to ride up the tiny footpaths, across roundabouts on the inside lane into the traffic, diagonally across intersections, through red lights etc etc... no surprise dozens get cleaned up every week.
You'd think they'd give em a leaflet or something when they get off the plane.