Having said that, if you manage to drink this much without anyone noticing in your professional performance, I don't see why that should be a reason to not employ you or fire you (although it is hard to say that in advance). The same goes for cannabis, which has a much less severe impact on your ability to function in society. In The Netherlands, Alcohol is actually considered to be a "hard drug", whereas cannabis is a "soft drug".
Regarding flashbacks, I did read of adverse effects of LSD years after using. I have never heard about the same applying to mushrooms (a completely different chemical).
http://www.google.com/search?hl=en&source=hp&biw=135...
I'll admit, I'm old and my learning (through bartender's school, no less) reflects that. Most shot glasses will hold a jigger, but you don't fill it for a shot. Further down the page you linked, under "jigger," shows a tool we use(d). A "shot" was a drink, the "measure" was a jigger (1.5 oz) or a shot (1.0 oz). In programming terms, the word "shot" was overloaded.
Weird I've thought a shot was an ounce all these years.
I have often enough drunken half that, 1/4 bottle a booze, three double-shot drinks over the course of an evening 4-6 hours. It's definitely not enough to be drunk at that rate or even tipsy. I function just fine. Double that I would be rather tipsy and not enjoy it. But I have known people that polish off a half and even a whole fifth in a single evening. I suppose those are the drunks. They usually function perfectly fine at work and are often top contributors.
I've never smoked pot myself but I know plenty who do and a lot of them are really fine developers, even though they get completely wasted every single evening.
The people that seem to be negatively affected in work are the amphetamine and narcotic users, both of which are often legally prescribed to them for ADHD or back pain. Those folks can get a bit edgy.
As far as flashbacks, I did know one LSD user who had them. But this guy had been very irresponsible and done several dozen hits one day which landed him in an insane asylum for over a year, after which he remembered nothing. He was definitely messed up. Casual users I know of hallucinogens have told me they've never had a flashback. I have noticed though that long term casual users tend to become more and more flaky so I would consider that a negative in a job interview, except that I don't ask such questions of people in that situation. I am skeptical of the claim the authorities made that the person in the referenced article is genuinely at risk of flashbacks because of a single incident of mushroom use years ago.