Ermmm, Jeff you know I know you're a knowledgeable guy and all that but two things:
1. In my experience, blades flying off usually has nothing to do with the prop itself (unless it's a Mercury prop which are thin and light but at least they're cheap and fast). Usually there is a problem elsewhere, causing vibrations (not necessarily perceived by the driver) and moments of force outside of prop design parameters.
2. Why did you have anything engraved on an expensive set of props? If this process does not fragilize what is a fragile piece of equipment, then even the slightest uneveness on the surface is enough to cause unexpected stress on the blades, stress which was unaccounted for during the design and manufacturing process.
This is why even the slightest ding in the blades should be repaired immediately otherwise prolonged use may cause further and unrepairable damage.
Props may feel all heavy and look tough but are actually fragile things designed for only one purpose. They are not meant to bounce around in the back of trucks, have any sort of engraving done on them...