It depends on the airport. At Dulles International there is only one security screening point and once past that you can go to any terminal area. At Washington National, and a ton of other airports, each terminal has a seperate screening area and you can only use your ticket to go to that terminal.
However, if you have an airport authority-issued gate pass with your picture on it, you can use that to enter all of the security check points in the airport to get to the terminals. It will not admit you to other secure areas in the airport.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.