I mean, I think discouraging jaywalking on a major corridor is generally an ok objective in service of deconfliction and especially so in the vicinity of a playground. Something like a low fence, wall or guard rail isn't particularly visually intrusive, and while it can be hopped, that's usually enough to deter. I'd also personally read "protect the frontage road" as "stop SUV drivers from seeking a convenient shortcut by driving over the median to the frontage street." Example from the Casey Overpass project, where they similarly protected the frontage street with a low wall.If planned vehicle speeds are high enough to require a guard rail for feeder streets, we are leaving a lot to be desired with this design. It doesn’t seem logical to protect the frontage road while leaving only the curb for the cycle lane on the other side. The impression from the neighborhood meeting was that it is potentially a fence to prevent jaywalking.
Looking at the render, it's shown as a fairly low and unobtrusive fence akin to that surrounding the playground.