Both documents are visas for planning (i.e. somebody can plan X, according to some upper bounds). The construction permits come a few months before construction works begin.

Marking them as proposed creates more work later since you can't draw it exactly and it's always easier to draw it from scratch instead of adjusting each node (when new imagery comes in X years).

Creating notes only when construction starts, won't work either. People usually find out about such plans through local knowledge, school involvement, or if they happen to see documents like the ones linked here. Other than that looking at the blank (in terms of notes) map of their immediate surrounding, they have no way to know that something is going to happen (or might be happening at the moment).