Do all flashlights slowly discharge when not in use?
I do the exact same thing and have an FC11 in my backpack for emergency use. I do untwist the tail cap just enough so that when you press the button, the light doesn't come on. I feel doing that is more a safety measure to prevent accidental turn on than the battery discharging since, as other have already pointed out, the battery will only very slowly self discharge. I've left my light in there for 2 or 3 months at a time and just check on it and recharge as needed.