There is no problem with emptying a cylinder. It is utter tosh that if a cylinder is emptied it must be inspected.
Cylinders corrode internally if they are filled from inadequately filtered compressors where the moisture trap is not working, not through being emptied. We sell hundreds of cylinders a year, the cylinders come from our supplier in Italy and the valves are made by MDE in the UK and we put them together when they are sold. They sit for months in our unit without valves.
To ship on an aircraft, just empty the cylinder and be done with it. If you are really paranoid about being stopped then take the valve out and put a bit of masking tape over the neck or if you are really nice to me I will send you a funky little neck plug that you can screw in. For real belt and braces put a little silica gel pack in the bottom.
Same as most won't sell you oxygen. Or they might when a particular individual is on the shift... been there, tried that
To be fair, you seem to be the only one who has this problem as has been demonstrated by comments elsewhere!
