There is a problem because regularly scheduled buses are permitted. I'm analyzing scheduled bus parameters for cities around the world, using their GTFS schedules. One problem is that many do not include the optional shape file, which traces the route. OSM does provide some bus route "shapes". However, they are not updated with transit agency frequency (sometimes daily).

My workaround is to use the stop  geographic locations, which are required, and trace the shortest distance between stops along the roadways. Naturally, I don't include those with "highway": tags like "cyclepaths", "bridlepaths", etc. as possible "ways" to connect. I have been omitting those with the "access":"no" tag.

There is a similar problem within the Brooklyn Navy Yard. A scheduled bus does go through the facility. The workaround has been to include a tag "bus:conditional": "yes @....", in addition to "access":"no". Perhaps, a qualification of this sort might be in order.

Just a thought.