When I last sailed out of Barcelona, there was a liquor store at the gangplank. We stowed our luggage then went back down repeatedly to stock up. One member of our group is a beer drinker, and he brought a couple of cases onboard. Laughably, there was an unmanned "amnesty" table between the liquor store and the gangplank with instructions to leave any liquor behind. If there had been any, "someone" would have taken it. 😁
Pretty much all over Europe, the liquor rules aren't enforced.