MDA is correct, no need for a boarding pass to get through security.
I imagine it would be possible in the right circumstances to get past the gate staff without a boarding pass, (gate person sorting out an issue with another pax), but highly unlikely it would go unnoticed, as this occasion proves.
Have to agree, a storm in a tea cup.
I would go as far to say there was no security breach, the system worked.
In fact, even if you don't go through security as such (to the commuter aircraft and GA area) you still need to present a boarding pass.
No boarding pass the be in the commuter GA areas either. You need one to get out the gate but not to sit and wait.