Speaking for myself, my logic doesn't consider the neighborhood roads owned by the neighborhood. I consider it public, and as such I don't think cutting through the neighborhood is illegal. I just consider it something almost like pissing in a swimming pool. They aren't asking for this extra traffic and it is after all their neighborhood. I wouldn't like it happening in mine either.

What we should have is better infrastructure on the main roads. The whole point is that they go faster than neighborhood side streets; and if that's not working then something isn't right. More or better public transit, more or better bike friendly roads, homes closer to work or telecommute. Or maybe the cauliflower neighborhood design, where basically the neighborhood is a maze, there's a mandatory 90 degree right or left turn ever 3 blocks, so it's totally pointless to use such a neighborhood for rat running. And it's not super expensive to retrofit a neighborhood this way; certainly it's more pedestrian and cyclist friendly. Plus it also slows people down automatically, no one is going to rip a 90 degree right going 20mph.

So you take all the acrimony, regulations, fines, speed bumps, dips, ugly signage away and just design the thing to be driven the way the neighborhood wants, and not designed for rat running.