As for other security protocols, most of it is "Capitan Obvious" grade stuff. Those guys have the balls to go hijacking Al Queda safehouses and caches, and they damn sure would hijack your weapons stash if given the chance.

There was a mall shooting not far from where I live where one of these characters stole an AR from a guy, apparently some home built rig which jammed up on him. He was not classified as a Jihadi, they said "mentally unstable individual" in the news reports, but other elements of that smell too much like a self radicalized early bird IS. Their plan, like the attacks in Europe is that they pull something off either before heading to the IS, or if they find it impossible to go (hence the CIA plans for discreetly facilitating their exile on a case by case basis). If they are fresh out from an attack, then they won't make it, that's the plan. If they just sold their shit and got passports (which they burn upon arrival), then so be it. Maybe track them, and the standard offer being that if for whatever reason they decide they can't handle jihad and want a pipeline out with complete debrief, maybe something can be worked out. That, in fact, is where a lot of the most current intel is coming from. If they self radicalize and self organize their own pipelines for getting their own people out of the west with no agency involvement at all, then that's the problem right there, it means they can go with plan "A" which is to do some damage then leave.

According to the Germans who managed to get into and out of the IS and do their own psych evaluations, they don't consider the people coming out of the IS to be the real threat. The reasons they leave the IS is they were rejected or flunked out somehow and don't really want to go back. They smoke tobacco, or weed, they might be queer, they might just be useless lazy fucks or exhibited cowardice on the battlefield. They thought maybe they were radical but were proven by their own kind not to have the stomach for it. The ones you would then need to worry the most about are like the Tsarnaev brothers. They want to pull something off that gets them a victory welcome parade when they show up to the IS. Maybe not 99 virgins in paradise, but if they make it, a victory parade and bevvy of bitches volunteering to be their harem, that, apparently the IS can arrange locally there.

That means you are better off trusting a criminal felon with access to weapons than those people. They don't work at gun shops, they don't get around police or military armories, they don't work at gun and ammunition factories, you politely keep them at arms length in any patriot movement stuff. If they go to a gun shop and buy shit with a background check, then that's them. If they are buying a dozen AKs at a time fast and furious style, then informing to the FBI does not make it cool, you find an excuse not to do the business, period, done, shot called. Hadji mart owner wants a .357 for protecting his cash register from the ghetto goblins, OK, fine. He wants a half dozen FN FALs, uh, no dude. Fresh out...

Be polite, have a plan...