For what it's worth...

More than a decade ago I bought four toy "Insecto Bots", new. They came with
three AAA alkaline cells installed, from some totally unknown manufacturer.

http://www.amazon.com/247999-I-B-53-.../dp/B000TQC9AO

I'd opened them a few times to check, and the cells had not leaked. They still
powered the units, though a bit weakly. The other day I finally discarded
them. There were no signs of leakage.

Yes, cells leak, and yes, Duracell seems more likely to leak than others, and
yes, I've had leaking cells on rare occasions. But why some people here have
had such terrible experiences, I don't know.

If it'll make you feel better... About ten years ago I bought a box of 1000
AAA Polaroid cells on eBay. They're wrapped in pairs, in cellophane. About a
quarter of them have leaked, producing a powdery deposit.