The above threads have the answer, but which is right?
1)Easiest solution would be to remove the battery when you're done playing for the day. (#9)
2)Make sure the meter switch isn't accidentally pressed when the camera's put away.(#3)
The camera can be checked for battery drain by putting an ammeter in series with the batteries. This can show whether the switch is bad or not.
#9 is by far the easiest and least expensive.