This is a big if, did they really point the airsoft at somebody, even if they didn't, allowing someone to see who is untrained and may call in on you, can be big trouble depending on the constabulary around you.
I love airsoft, but keep it out of sight of the public. If they both had the orange rings around the muzzle, then in MHO, they should have been told to expect such treatment, as the public has no distinction between real and toys, and most airsofts resemble their counterparts beautifully. But they have broken no law, if they pointed said toys towards anyone, then, Sorry all bets are off. Many convenience stores have been robbed by BB pistols that look like 1911's. In this case the terrorist angle seems a big stretch. However, could a group of terrorist, rob or control a group of people with airsoft guns, with the orange rings removed, that look like MP5's, or M16's, at least for a little while.
I'm a big airgun fan, and had a range set up in my backyard. The law was called on me, and when I showed them my range, they said, you not breaking any laws, but maybe you could do it differently. My high powered air guns are loud, so now I shoot Aquila super colibri .22rf's which is illegal but much quieter, and have no problems. Of course I have never pointed any of these airguns or firearms at anyone.