Here is a situation that came up this weekend:
Playing #2 at Cat Hollow (sorry, I am too lazy/stupid to post a link), the basket is visible but the landing zone is not. I threw a pretty good drive with a white star Mako, and another guy threw a good drive with a black Aviar. As we approach our lies, a guy from the group at the #3 tee says "that black disc hit that white one and knocked it six feet away from the basket."
My understanding of the rule is that a disc at rest that is moved by another disc should be placed back in its original position. However, none of us actually saw it, so I played it from where it was, and hit the birdie (six feet shouldn't really matter, right?

)
So I think we played it correctly, since none of us actually saw the disc being moved. But if we had seen it, could I move my disc back to its original lie?
Feel free to Prerube.