If they were running a "test run" they'd have started with perfectly normal behavior and worked their way up until someone noticed, don't you think?
There have been previous problems. This wasn't trip one.
They deliberately provoked a reaction
I haven't had time to look & verify this but I've heard that they had one way tickets & no baggage. Then they all ask for seatbelt extensions & start praying in unison.
Either a lawsuit in waiting or one step in sensitivity training, al qaeda 101.