Good Info !
This especially applies to the 9 Volt batteries used in smoke detectors because most people replace them on an annual basis, and there may still be significant power left in the battery. Most other batteries like D, C, AA, and AAA batteries have terminals at each end of the battery and less likely to short out, as well as they are typically used until they are dead, and so they have little if any power left in them when they are replaced.
I think this might also apply to other types of batteries like Cell phone or old laptop batteries....We replace them when they don't hold a charge very long, but they still have power, and the terminals are usually next to each other where they can be easily shorted out.
Gary, Thanks for sharing this tip. I will definetely be more carefull of how I dispose of my batteries.
...Rich