I never heard the seagull story, but it could be true. The ECM gear was quite potent. I doubt that an EA-6B ever shut down power on the eastern seaboard, but they used to inadvertently pick up the radio and TV stations in the Seattle area from their range in the Pacific Northwest and put them out of business until the equipment was turned off. So I can believe that they would shut down communications.
It is truly an incredible aircraft.
I doubt the EA-6B "seagull" story. When I worked on E-2C's, the "Weight-on-wheels" switch would prevent the radar from transmitting through the antenna while on deck. (The radar was equipped with a fluid cooled dummy load, so they could transmit into it.) The WOW switch could be bypassed with the "Battle Short" switch but this was normally shear-wired to prevent inappropriate use and to indicate that it had been used.