I support cyclists' right to use MUPs and roads - but so many of us flout the laws as to give a terrible image to the non-riding public, as well as putting others and themselves in real physical danger.
I think the answer is police attention to the areas where rules are broken - either at intersections where bikes often blow through without stopping, or on MUPs where cyclists treat it like the tour de France... I'd bet that as soon as word got out about a handful $200 fines for 'dangerous operation of a vehicle' on MUPs, you'd see a whole lot less reckless behaivior.

We have a problem where I work - cycling is allowed on the site - a ~50 sq. km government owned area, but there is a particular intersection next to the designated bike parking that bikes are constantly blowing through a stop sign. I think a lot of people were surprised when I suggested we ask the local police to stake out the intersection for a couple of mornings to nail everyone who does not come to a stop at the stop sign. THere was rash of fairly minor speeding violations on site by cars some months ago and I got a ticket, as did many others, for doing over 60km/h in a 40 km/h zone. People now drive a lot closer to 40 km/h in that area.