Directions for many appliances, photo or otherwise, warn you to remove any batteries when the unit is not in operation for some time. Generally this is suggested to avoid slow drain of the batteries (which can occur in some electrical circuitry, turned off or not), or to prevent minor oxidation/corrosion which can cause poor battery connections or no jiuce at all. Leave a battery in place for a long time, particularly under warm and humid conditions, and chances and humid conditions, and chances are you’ll have an icky mess on you hands as well.
In the hope that you will do as I say and not as I do, I’d suggest removing your batteries and storing them separately whenever any item isn’t going to be used for at least two weeks.
Surprisingly, I find it is just as important to remove batteries when cameras, flash units or other battery eaters are to be packed for transportation. I can’t tell you how many times I’ve packed a flash unit which somehow came into contact with an object that turned said flash unit on all by itself. I have done likewise with cameras that require a light touch of the shutter button to turn on. Recently, I burned out the printing heads of two portable battery-operated computer printers in the same manner.
While I can emphasize careful packing, taping of on-off switches in the “off” position, plus other safety checks, I find the safest, simplest and easiest measure is to remove one or more batteries for traveling. I no longer surprise or amuse passengers on airplanes with the muffled ringing of my alarm clock or the whir of my portable electric razor coming from my locked luggage.
~Keppler, Herbert. “When travelling remove batteries.” Modern Photography 50 (1986): 7