Rock Salt for Hay Preservative ???????

I've read a bunch of posts on various forums where some folks will sprinkle rock salt on the layers of square bales as they stack them. They make it sound like the cure for high moisture hay as it dries our the hay and prevents dust and mold.

I'm having a hard time with this one.

Rock salt on squares - does it really work and if so - how and if it really works, why aren't we all using it or university studies recommending it?

Rock Salt for Hay Preservative ???????