Teenaged boys taking their younger siblings out for ToT looked a bit annoyed because they only got one piece while their kid sister in the Princess Mononoke costume got 3.
And, more seriously in the tone of the OP, army surplus jacket & a knit cap are actually kind of the norm for teenagers around here in October (my default understanding is that their ‘costume’ is ‘war veteran’, which is why they get one piece), so unless they were wearing a fake beard or an ammo belt, I wouldn’t even recognize it as an ISIS costume. However, adding all that would get them more candy.
Sad how they can ruin a perfectly good acronym. I remember a specification for the “Aircraft Information Distribution System” written around 1984. Bad acronym timing!
Back to ISIS: I used to work in the “Intermediate System to Intermediate System” protocol, but fortunately everyone usually puts a dash in that one. Well, I often didn’t bother, but I might now.
Back in 1977 at age 20 a few friends and I went to Halloween parties as terrorists. We didn’t catch any flack, but thinking back on it now, I wonder if I was being an idiot without a clue. Chances are good. I’d certainly consider it poor taste today.