If you have a head ache the night before a flight and take a panadiene to dull the pain and rock up to work the next morning and get tested I think you could find yourself in trouble.
Stood down at minus 60 minutes to push back? I don't know about your company but mine doesn't happen to have a couple of pilots just hanging around just in case.
So basically you are going to be the reason for a MAJOR delay. There is no doubt the rumourmill will be hard at work and before you know it "Mr. Hat's a junkie."
I don't have any reason to be concerned as I don't use illegal drugs or drink to excess. But I am concerned that when I'm feeling unwell I'm now not able to take an over the counter medication the night before.
Anyone that is in the process of convincing themselves that its going to be all okay may want to have a hard think about it. My question is - what happens to your medical? Could you be setting yourself up for increased surveillance?