So, is the apron on its own enough? I assumed it needed to have something on top of it (dirt, rocks, etc. - I'm using big tree logs and rocks).
The apron needs to be pinned down with landscape pins, but can be put right over grass. The grass will grow through and you could mow over the wire, if it doesn't stick up. I used mulch to cover mine, because it was at the edge of woods. You don't want big stuff covering the apron, because predators will start digging beyond them. If the predator starts digging at the base of the run it will run into wire and move left or right. They don't think to move backwards. If you have big rocks they will start digging where they end, out from the base of the run. Hope that makes sense.