Originally Posted by Sweetone
1. A passenger putting something in the galley or lavatory - of course depends on what it is.
2. An individual or several people trying to distract or block a FA.
3. A glimpse of some type of prohibited weapon - a real one, not the bogus liquid type.
4. Sudden changes in behavior - such as a group seen together in other areas of airport who suddenly act as complete strangers
5. Adults who pay too much attention to children traveling alone. (I'm a mom)
Of all of those, the only one I've seen in decades of travel is #5 ... and even then it's subject to interpretation.
I've never seen inappropriate attention toward children, but I have seen weary road warriors who missed their kids warm up to well-behaved, cheerful kids who were marvelling in their first airplane ride.
I still laugh about that one flight with the two unaccompanied children. The sister was maybe 7 and oh so in-charge and responsible about making sure her well-behaved 4 yo brother stayed in line. Simultaneously serious, touching and funny. Good times.