On our big ride every may, they have local police and sheriff deputies of the counties involved at almost every intersection controlling the traffic. Partly because it's organized by the city I live in.
The other rides organized by others have some law enforcement covering intersections, but never enough.
I don't know that there is a perfect answer for your question. While some imagine that the intersection is instantly flooded with cars when their light turns green, others are probably imagining being stopped at a red light with no crossing traffic.
Here, a large number of motorist in crossing traffic are going to stop if they see a crowd of cyclists at an intersection. So it's a damned if you do and damned if you don't situation when with other cyclists.