It's not a structural repair in the sense that it doesn't see broad tension stresses over that area of the board (like the outer skin at the mid-point of the board would see). Also in the sense that if your repair fails, it will not compromise the structure of the board. High modulus fibers excel in tension as opposed to compression. The trailing edge sees crushing point loads (in compression) on impacts and my point is that placing high modulus fibers in something that sees this kind of focused compressive loads doesn't really add much over using fiberglass or even just fumed silica as a thickening agent.