In my version of the solution it matters not when people get fed to the sharks.When do people get fed to the sharks? Immediately on error, or en masse at the end? In the former case you can recover from an error. In the latter I think pretty much everybody dies unless somebody else slips up and cancels the error.
If a given prisoner guesses his hat color incorrectly, he could be fed to the sharks immediately, or the warden could remain silent and wait until everybody is finished guessing, feeding all the wrong guessers to the sharks at the very end. Either way.