I doubt the bar is particularly high and the onus is on the city to create signs/paint curbs to indicate if it's longer or shorter. As it stands, if there's a

I doubt the bar is particularly high and the onus is on the city to create signs/paint curbs to indicate if it's longer or shorter. As it stands, if there's a red curb or parking prohibition sign already next to a crosswalk, it dictates distance - whether longer or shorter - and there are a lot of intersections with those already that are much shorter than 20 feet - like where fire hydrants often are. If SF doesn't repaint/resign those, then nothing happens. It's only for unpainted/unsigned areas where the 20 ft rule comes into place.