Done it in a Berliner Weisse. Contributes very little IBU (a high IBU is said to inhibit lactic bacteria) but still provides anti-bacterial properties from the hops.
I'm guessing a bit here but think it likely was what they did in medieval times as most beers then were raw ie no boil, now it may be good for a mild where you don't want much flavour or bitterness just for preservation.