Dave:
Valid concerns. But the rings still push against the body, the tape to body contact compresses the tape, and the tape tabs keeps the lenses from moving. So nothing moves around - in fact, since the tape has a slight 'grip' on the lens itself, the lenses are as solid as if you used silicone. And it's much easier to remove the lenses for cleaning.
I've got a bunch of lenses in aluminum bodies this way.
(Since the aluminum bodies are 'spun', the openings vary up to 1/8" in diameter.)
I've never had a lens come out from behind a 'taped' ring.
Jim
