I'm tempted to just say "Exactly." and leave it at that, but it wasn't obvious the first time, so...

For some reason, TSA seems to think that wanting to go to the gate area, without a ticket, is suspicious
behavior. Also, purchasing a one way ticket, or using cash to purchase a ticket are also well known
"red flags". So, purchasing a round trip, refundable ticket simply to gain access to the gate area
makes as much sense for a suicidal terriorist as it does for a Dad to see his kids off.

Or, to come at it a different way, terrorists who have no intention of flying can gain access to the gate
area with zero additional trouble. Simply buy a ticket. So why does the TSA hassle people without tickets
who want to do the same thing?