Legal age to have alcohol with dinner is 16 in Scotland, and in general it’s 18. In Canada it’s eighteen or nineteen, depending. I think it’s kind of silly to tell S he can only drink if it requires a passport (we travel both places), and he’s generally a responsible human being so I’m not particularly worried about it. D simply doesn’t like the taste, so that’s that.
At the graduation party we just hosted, though, we reminded the kids in attendance that more than one of the adult guests were LEOs, so they should probably not expect to get away with any fast moves. (And then we moved the beer into the fridge, and put the sodas and water in more easily accessible coolers.)