I see the most leaks in toys. I think it has to do with parents who forget about the toy and don't take the batteries out or the fact that most toys from my experience drain batteries unevenly aka they will drain one cell almost completely then the other cell will be totally full as if it were new. Some toys also get left turned on which means the batteries will completely drain which is more likely to cause a leak. Because of this I would be extra careful with alkalines and toys.
An excellent posting and with the price of toys these days.