If these guys were really testing the waters, why would they expose themselves and have their lives, cell phones, records, associations, etc., exposed and scrutinized by Gov't Security Agencies?
It would hurt their infrastructure, IMO.
If 11 people got on a plane like that and caused that kind of commotion there is absolutely no way they'd be allowed back on the same plane, even if they did a search of all their stuff and found nothing out of the ordinary. Those 11 people would be brought back into the airport and detained for many hours, and questioned by many different people. Never in a million years would they be allowed back immediately onto the same plane.