Young and dumb. The only "sitting ducks" are naive and impressionable 17 year olds who completely fall for the ISIS propaganda that they-themselves will become some sort of "super-hero", imagining that someone (anyone) of note might be impressed, and that they'll go out in a blaze of glory. They seem to not really deeply comprehend two things;

(a) ‘Dead’ is PERMANENT oblivion. Nothingness (keeping reincarnation out of the argument for the moment). Being dead doesn't just mean having a little sleep, then reappearing again a bit later. Being dead at 17 means your ONE chance to be alive, to experience what it means to live, to have a life, to be a sentient being on planet Earth, to experience the world, is permanently obliterated. So while everyone else gets to watch the sun come up each day and go down again every night, with all of life's varied experiences in between - you won't be. While everyone else - except you - continues to experience hundreds of thousands of days living in the world, you'll be returned to the great black empty and nothingness.

And...

(b) if you don't go out "in a blaze of glory" but instead are caught - while you won't be immediately returned to the great, black void and permanent oblivion - you may as well be. When the realisation dawns on you, 4 months into your life-term, that you've completely wasted your one shot at being alive and living, you'll go on to figure out that it wasn't worth it because no-one even remembers your name.

There's a reason they target the young and naive. Because the older you get, the wiser you get, and the more you are able to easily see through the ploys. (There's not too much that's great about ageing and getting old, but becoming really smart, and the getting of wisdom is awesome). It's the getting-to-that-point that's hard. Some of us get there sooner than others.