I'm in the bay area and adecnotally it has been very inconsistent for me. Here are a few I dug up in just a few minutes of 4-way stops without 4-way labels. This has led me to mostly disregard the absence of a 4-way label as a source of information.
I'm "that guy" in my area that reports and tracks and eventually shames-via-local-newspapers anything I find like this (and trash dumping etc.) Maybe you could be that guy too? This seems sort of dangerous.
I could, though I really don't have time to drive around on street view and keep doing this. I found these violations within a few minutes, I'm sure I could spend hours and map out several hundred such intersections.
Rather, I would be more interested in mapping out all the violations on a mass scale using neural nets, though I'd want my time funded to do something like that, considering it takes away time I could use to do other things.
I hear you. Our time is limited. But I would argue that most good occurs due to many small interventions. And seeing these interventions and the improvements can encourage others to intervene. Maybe reporting these kinds of issues is too hard and that's the problem? Maybe a blog post describing how you just wasted 25 minutes filling out a web form and how a safety issue like this does not look good for the local governance? (This is all really obvious, but I'm clearly just trying to reframe what "that guy" could mean to you and anyone scrolling by :-) )
