I suppose they're cashing in on the market of women that go out on a Saturday night, get drunk, have unprotected sex but have work to worry about on a Monday so can't make an appointment to go to the docs then, therefore have to buy it at the weekend/in their lunch break.
Not saying that all women who take it are drunken hussies, I've taken it before but that was years ago and from the family planning clinic (actually got a friend to go and get it for me).
I imagine they're trying to put people off using it as a method of contraception.