When making golf clubs I used to insert weight in "Wood" (Hollow metal ballons in shape) heads that needed some extra weight by injecting tungsten powder/resin through a hole and using it to hold tungsten powder in place. I just put a tape over the hole and let the epoxy fill in the hole. I think your approach should work fine, though I wouldn't recommend drilling it, unless you know where you can safely put a hole. But if there is an available hole...

Anyone know if the tag is magnetic? If it were one could epoxy a rare earth magnet outside the tube... Hold a magnet to the tube and see what happens. Might end the ID function...