I think there's massive differences in circumstances. For example you've got things like the Nate Campbell example, where I believe he just physically could not make the weight because of his age and apologised profusely for his unprofessionalism afterwards. I'd let something like that go. Then you've got situations like Mayweather not making a catchweight, while it's a bullshit move, I think when the other fighter who wasn't draining to begin with makes another $600,000 out of it, that's a suitable punishment, particularly when both sides agree to re-write the contract in advance.

However, where I do agree with you is where guys have clearly not even tried to make the weight like Guzman or Castillo, then there should be some kind of more serious punishment. I think that for every pound over the weight they are, they give up 10% of their purse to the other guy. That would have left Guzman with just 10% of what he was originally guaranteed. I also think that they should to compensate the other fighter for all training costs, which in cases like Guzman or Castillo would leave them with fuck all and rightfully so.