Wearing pyjamas is really no different from wearing the standard D4 Yummy Drummy uniform of Uggs/Dubes/American Eagle/Abercrombie etc. It's just a fashion thing. I really don't get why people worry about such things.
Is this not the whole point though
If you want people to see you as a "D4 Yummy Drummy" then you will wear the standard uniform of all the stuff you mentioned (never heard of any of them TBH but I'll take your word for it as a man of the world!)
If you want people to see you as a skanger then you will wear the standard uniform of pajamas