When the player sets /fly to true, they are immune to all forms of fall damage. By this I mean double click SpaceBar to activate - fly around and deactivate and then walk off a tall block - there will be no damage done to the player. While this is similar to mods such as CJBs this isn't the same as it would only happen if you turned fly off completely. This works 100% of the time. Those who do not have access to the /fly command, do not get this problem
