Its one of those rare but real risks I guess. At work they started out recycling batteries and early on they required 'tape both ends of each battery', 9 volt or other. I dutifully taped both ends of ~30 AAs and it was a pain. They since have revised down to taping *no* batteries and are none the worse off for it. Probably the Risks folks haven't heard about this one - but with no recorded fires in the recycle bins who would raise the issue...