Drilling a hole in a cylinder is a stupid way of rendering the cylinder unserviceable. In OZ you have to do more than this, saw the neck off or cut down the neck so it is impossible to repair. The standards say "with the permission of the owner" cut into pieces or crush. If the owner does not consent then "FAILED" shall be stamped on the neck.
I discussed this issue with a filler one day and he said he saw a cylinder come in for a fill with tape around it. He thought it was strange and then recognised the cylinder as being one he had failed just recently. Removing the tape he found the owner had threaded the hole (that had been drilled to make it unserviceable), and put a bolt in it, then taped over it. A bomb waiting to happen.
I discussed this issue with a filler one day and he said he saw a cylinder come in for a fill with tape around it. He thought it was strange and then recognised the cylinder as being one he had failed just recently. Removing the tape he found the owner had threaded the hole (that had been drilled to make it unserviceable), and put a bolt in it, then taped over it. A bomb waiting to happen.