"surely no one would try to "fake" a watermark or the like without having an intent to deceive."

The manfactures tell me anyone with the ability to fake a chip can fake the UV markings. I recently seen some that were made in the Orient and passed in a Hong Kong casino. Several million $ worth.

This is one reason the Palms opted for the new laser technology for their rack chips. Only we can see it with our laser lamps tuned to the right frequency.
Even Dick Covington can not read the chips.