This is a sensible move that actually protects us. If you are PXing in uniform and on the GD you have been on duty and could be breath tested on arrival (pathetic but the way the world is going!). If the test is positive, even if you are not type-rated on that A/C, before common sense prevails the press will have run with the story and your career will be over!
I agree entirely and to suggest the company are doing it to save money is bordering on paranoid. It is simply more 'nanny state' nonsense, nothing to do with the company on this occasion.