"If you see something, say something," the Department of Homeland Security tells us.
Problem is, a lot of folks probably need a little coaching on what "something" is.
"Something" is not someone on an airplane who made a phone call in Arabic.
College student Khairuldeen Makhzoomi, 26, was booted off his Southwest Airlines flight in California last week because a woman sitting nearby was freaked out hearing him speak Arabic when he made a quick call to his uncle before takeoff.
That is speaking another language. It is not terrorism.
"Something" is also not a student who made a clock and tried to show it to his science teacher.
Ninth-grader Ahmed Mohamed, 14, was interrogated, handcuffed and arrested at MacArthur High School in Irving, Texas, for bringing his homemade digital clock to school last fall - teachers thought it might be a bomb.