It seems that I might have opened a can of worms here!
I know of a lot of beer kegs that did feature some sort of external pressurisation. The old "Four-and-a-half" had mounted on its top a non-return valve of the type also used on bicycle tyres; and indeed was often pressured by means of a bicycle pump (seen that more than once!). As for the selection of glasses, I don't recall any of my drinking acquaintances being too fussy about which type of utensil got used. In fact, there were more than a few social occassions in which beer was consumed from china tea cups.
Nobody in that photograph was flat on the floor - yet. Just like there are various stages of consciousness, there are, too, various stages of inebriation - ranging from just mildly "tipsy" right through to an alcoholic coma.