One thing I do wonder about...
We have a large lake here that has a different tournament just about every weekend in the summer. Let's say someone cheats and puts metal in a bass, it's not detected due to it being small club that doesn't bother, the bass is released, and the bass is caught the following weekend in another bigger tournament that does use a metal detecter/xray. This time metal is detected and the angler that didn't put the metal in is blamed? Possible?
As a taxidermist I have found things in fish stomachs that didn't hurt the fish initially, but it was obvious they were too large and solid to pass. Would have killed the fish eventually, but not for a while.