Originally Posted by TSORon

A guess only, but I get the feeling you had an encounter with a Behavior Detection Officer (BDO). Their job is in particular to observe passengers for behaviors that might signal a threat to an aircraft. Asking questions and providing advise enhances the officers ability to observe actions and reactions, and therefore assists them in their job. Being nice while doing so also helps them by not presenting a threatening presence when talking with the passengers.

Just a guess mind you, but it sounds about right to me.