I think the most important thing to keep in mind is this.

On the road, a bike is the little, slow victim. On a MUP, the bike is the heavy, fast danger.

We, as cyclists, need to remember and remind each other when we move between modes, and we need to change our riding style according to where we are.

My typical commute is 8-12 miles of roads. and 4-8 miles of MUP depending upon the route I take. When I look at the splits after a ride, what I find is simply this. On the road, I ride like a bat out of hell, with top speeds over 40, and averages around 20. On the MUP sections, my averages are around 12, and almost never exceed 18. Why? because as soon as I transition into the MUP, I sit up, down shift and go into courtesy mode. Respect the slower moving traffic, if you have to go slow behind a group of walkers due to oncoming traffic, DO IT. You are the car that you so hate on the roads. Don't be THAT driver/rider.

We as riders need to be educating other riders, and understand that the ones riding like boy racers on the MUP's don't want to hear about their bad behavior anymore than the car drivers that so annoy us (And are frequently one and the same)