Salting bones for stock
So, we just went to a local restaurant that has a butcher counter. We bought some beef bones for making a brown beef stock, and the young hipster guy behind the counter proceeds to tell us how to make stock (we didn't ask--he clearly just assumed we didn't know how, which is a little annoying). He informed us that we needed to salt the bones before roasting. I thought this was odd, as I've never added salt to a stock. I don't have a prohibition against adding salt, but for me stock is a sort of umami-rich blank slate--I don't want to start out with something salty. I'd rather add salt to individual dishes as I see fit. Part of me thinks that this guy was just being a bro-chef, getting a kick out of telling us how to make stock and not quite getting it right, but then maybe I've been missing something. Is there a salt-adding stock-making cult with which I am unfamiliar? Is there a purpose to salting beef bones before roasting them for stock?