The special security procedures for flights arriving or departing DCA (Reagan National) include a requirement that no passenger is to leave his or her seat in the first 30 minutes of a flight departing for or from DCA, or during the 30 minutes before arriving at DCA. Thus, for example, on a one hour flight from LGA to DCA, all passengers must stay in their seats the entire flight -- no trips to the lav -- or else the plane diverts to the nearest airport.
For particulars, see
http://www.washingtonpost.com/wp-dyn...2001Oct11.html
Not yet to the point of having passengers check-in 3 hours before departure so personal catheters can be installed. --And small wonder that train ridership on the New York Washington route is surging.