It’s all down to common sense really. In my opinion you shouldn’t report for duty with any level of alcohol in your blood, no matter what the allowance is. We have more than enough time to enjoy food and drinks whilst being on days off and well before any duty. If somebody needs alcohol to cope with stress and sleep disorders, than it’s better to go and seek some medical expertise which doesn’t automatically mean being denied a medical as there are loads of medications accepted by EASA and FAA for those conditions.