Chamfer the corners of PCB
PCBs are not knives. An edge won't cut you. If you have wires that can rub against the edge of the board, that's just bad system design, and you deserve whatever ill effects come from it. Chamfering would be a solution looking for a problem. If it's that big of a deal, V groove rather than route the edges. That gives a more angled edge. The better solution is better system engineering.