The third, of course, was the Cute Kid (there's always one) who had found all six by the simple expedient of grabbing as many as he could as fast as he could and worrying about sorting them out afterwards. Leaving me the task of putting 27 back out...
About a third seem to have vanished, so there may be more claims - or not if a lot of people have one or two each. Anyway, it seems to have aroused some interest; tomorrow and on Sunday I'll be running games and (hopefully) selling disks, so we'll see how it goes.