We have completed the Great Loop on our GB, and two trips up/down the ICW to the Bahamas, and we have seen no need to carry weapons aboard. Even though Kilkenney Creek in Georgia looks a lot like the set for "Deliverance", the natives are friendly and non threatening. I personally would be more worried about going ashore after anchoring in the Washington Channel in DC, and wandering down 14th Street in the dark. As previously stated, a flare gun at close range is an effective deterrent (Remember the scene in the "Ipcress File"). We have a four cell Maglite mounted near the cabin doors that should both blind and bludgeon an uninvited guest. Pepper spray is considered a weapon in Canada, but aerosol wasp spray has a longer range, and more impact on the recipient, plus it is totally legal. In Canada and the Bahamas, with more restrictive gun laws, we never felt threatened.
Enjoy your cruise.