Guest Check Out

Is there some sort of university assignment this year to create a cart with guest check out?

I can not believe the amount of people who are so hung-up on the idea, with out any real, evidence (apart from a few blog posts by random nobody's), backing up that it actually makes a difference, I can't understand why people are so ' desprate' to have it?

Non of the successfully online retailers have it, there has been no reputable research done on the subject, so all I can think is that its some sort of university module this year?

Answers on a postcard please.