Lateral stability; the board will slide until it reaches the edge and then it will fall off or flip over. Unless you have some sort of lip to catch the suspend

Lateral stability; the board will slide until it reaches the edge and then it will fall off or flip over. Unless you have some sort of lip to catch the suspended part, it's not going to be stable. Or you could use a tension member to hold it in place, although that breaks the aesthetic slightly.