There was an article in The Fisherman Mag about year ago. A surf fisherman caught a 36" bass at demo on bait, the bass was full of lead weights, and had a piece of rebar sticking out it's anus. I actually know the fisherman, and we couldn't figure out why someone would put that weight in the fish. Of course, we didn't know about this yo-yoing technic at the time. It was amazing, the rebar was rusting, like it had been there for a while, but the fish was healthy, and obviously still eating.
I personally think is a discusting way to catch fish, kinda barbaric. Fish live bunker, my guess is that's way more successfull.