what are you, on your period?

I saw Hot Fuzz again with my mother tonight (she found it amusing, though loud, and eventually got accustomed to the gore - although the "Pyramid Head" scene was a little tough for her to take) and noticed something odd:

is there some kind of inside joke about ordering cranberry juice at a bar?  Because that's what Sergeant Angel keeps ordering in Hot Fuzz (until he gives in and gets a Lager).  It's also what Billy Costigan orders in The Departed.  Where the other guy says it's a natural diuretic.