Testing when there is "probable cause" is OK with me. Professional pilots ought to be ready for it. I expect a blood test in the event of a crash just to eliminate the possibility that I may be "impaired" by alcohol. It may be well argued that I am "impaired" by lack of alcohol, but that is a different story!!!
Being a certified "silly old bugger" now as I am over 60, I am very careful to not be over the prescribed BAC to fly.
I carry my own certified breath test machine and use it!!
Come on guy and girls, you always know if it's probable that you will be over .02.
So, I will report sick if I think that I will be over .02 at sign on - end of story. All the old hero stories of flying with spectacular hangovers etc. etc. are dopey **** and I am ashamed to add my name to the list - just stupid stuff. Don't do it!!! I will never do it again.