Originally Posted by AfterThisNap
pitlocks aren't going to get tight enough in a horizontal slot to hold your wheel in place. It's been tried. The pitlocks are meant, like a normal QR, to hold your axle in a vertical dropout with enough force to keep it from falling downward with cornering/gravity. It's the frame itself that keeps the wheel from moving forward. They just don't allow enough clamping force.
Thanks AfterThisNap!! It's disappointing, but I wanted to know for sure. Thanks to everyone else who contributed here as well.