Mustafagander - you are so right in essence. However if a pilot attempts to go through the pre-flight process whilst above the very tiny alcohol limit , he or she has committed a serious imprisonable offence , and the Company would not have to justify dismissal.
If , however, an employee reported that they felt they had an alcohol problem, most Companies in Western civilisations would put them through a drying - out program , rehabilitation and back to flying.
The answer is - for those that have a problem - report it and let the Company sort it out at their expense.
I had a friend who refused to do that- offered his resignation after two drink drive offences within one week ,both in uniform ,and subsequently committed suicide.
If you do not have a problem , remember the limit is tiny. If your workmate says you smell of alcohol - go sick immediately and go home.