That is normal procedure when the "bar code" is raised.
Perhaps in this case it was just a discretionary option chosen by this airport's administrator.
I was at some airports recently and they made several announcements over the loudspeaker, requesting people to be alert and report any suspicious people or behavior.
People who are discouraging people from reporting suspicious behavior, are doing a disservice to the innocents, who may end up being murdered, because someone could have raised the alarm, and didn't.
If it's false alarm, no harm done, except a minor inconvenience to people, who should know better, than behave suspiciously, if they are innocent. If, on the other hand, they are terrorists, an alert bystander may foil the attack.
Another example is Richard Reid. If passengers and the flight attendant hadn't been alert, anothe plane would have been blown up.
I suppose John Valentine would have advised those passengers, to not get all paranoid, relax, and sit calmly, while Richard Reid blows them all to Kingdom Come.