I have come around some interesting (to say the least !) post from another discussion forum. That chap was wondering why do females have 'Zip' in their Jeans Ahem... just felt like sharing ..
Yeah, i'd assume it's so that they are easier to get on. Ever tried to put a pair of jeans on with the zip done up? Well it'd pretty hard...esspecially if they are tight. The button would probably pop off easily enough if you tried too hard.