The parent comment didn't make a claim about legality; it made a claim about enforcement:

> If you tried to pick up and drop off someone in a bus stop everyday, you would get ticketed for it.

And I can say, from direct personal experience, that the claim is wrong.

Muni buses now have cameras and there is a team which looks through all the footage spotting violations, even parking violations, and then they issue tickets.

The city should have enforced the traffic laws right from the start and not allowed these corporate shuttles to fester and develop into a now much bigger problem.