Starting at 1:45 in the video titled "Make the Call—Terrorism Prevention—The Threat is Real," a male authoritative voice states the following:
Cameras and recording devices have gotten so small, that most of us seem to have one with us all the time. It's not unusual to see people taking pictures or video almost anywhere.
But surveillance and information gathering is a common practice used by terrorists prior to an attack. If you see someone trying to conceal what they are doing, taking pictures of exits, security or restricted areas, if they hang around for no apparent reason, ask inappropriate questions about schedules or the facility, or if they try to avoid security when approached, make the call.