i would think that DCA is much more prone to it than BWI due to its runway set up. But it could happen anywhere. I know the other night at my station, our Air Wisconsin Flt 3955 that diverted here from YUL was taxiing out and an Air Georgian Beech 1900 almost hit each other the AWAC crew did a fantastic job making a sharp right turn away from the beech which made a sharp left turn as the beech was taxing in from yyz