I've put a bunch of overlays on with two-ton epoxy over the years and never had one come off. I never scored it with a hacksaw blade, though. I don't trust five-minute epoxy too far. The only overlay I ever had come off was purpleheart overlay on ipe glued with TBIII. The string broke on the bow at full draw, and it vibrated hard enough to crack and craze the finish all over the bow. About a month later, one of the overlays popped loose.
Cacatch, the main reason people use overlays isn't to protect the wood in most cases, it's to allow you to build skinny little tips that increase th bow's speed and performance.