I’m not a lawyer, but I would expect that if a kid becomes sick enough from drink on Purim to end up in hospital or worse dead then the “Well it was a religious thing” would not fly as a defense. I am pretty sure when they wrote that law they had the idea of a small quantity of wine at a kiddish or communion, not drunk to the point of requiring medical attention. Of course I’m not a lawyer and don’t really know what would happen in that case, but would not wish to find out.
Actually I’ll be at work on purim this year ;(. Its not a day off from us and due to other reasons I don’t have a vacation day to use