While Running, it’s difficult to distinguish other runners from the riders in the “nearby zwifters” display on the right side. The runner’s speed is indented a little more to the left. But that’s it. How difficult would it be to have the runner’s speed in a different color font - red, green, yellow? That way you could see other runners coming before they suddenly speed by and leave you in the dust.
I don’t know how things appear while running, but on my setup riding with AppleTV, in the minimap I am able to distinguish riders (light blue dots) from runners (brown dots). In the Nearby Zwifters list I can distinguish riders (power measured in w/kg) from runners (power measured in minutes/mile). It seems like it would be an easy thing, like you suggest, to change a color or add an icon to differentiate riders from runners.