Some pedestrians just refuse to follow any rules. There's one mile of MUP that I take on Sundays sometimes, because it avoids a climb after 55 miles of riding. The path has a dashed yellow line down the middle, and then each side is divided with a solid white line. Most single walkers stay to the right of the line, in their lane. Most doubles stay to the right, too. Then there are people who walk in clumps that spread 3/4 of the way across the path, and people who walk on the opposite side, and people who walk right in the middle of the path.

But it's not like there aren't cyclists who behave similarly. For example, Canada Road on the Peninsula is closed to motor vehicles on most Sundays, so the Park Rangers cone it off, leaving a couple spaces for cyclists to go through. Group rides will meet up there, often just inside the cones, so when the group gets up to about 5 or 6, they end up pretty much blocking the entrance, and they just stand there.

Also on Canada Road - which has big, wide bike lanes and a 50 mph limit, and a bit of traffic - slow riders who hug the inside of the bike lane, just at the line, so you have to go way out into the traffic lane to pass them, rather than riding more to the right, in a bike lane big enough to ride two up in.