Here are the official rules:
13. A Jockey’s weight at weighing in must not be:
13.1 more than 1lb less than their weight at weighing out; or
13.2 2lb or more heavier than their Declared Weight at weighing out.
13A The Stewards shall sanction the Jockey or Trainer, or both of them, when a breach of Rule (G)13.1 or 13.2 has occurred, unless the reason for the breach can be explained to the satisfaction of the Stewards.
So the Bacio case is clearly covered by rule 13A.
Mind you, quite why we have a horse that has never raced in Europe and never raced in a handicap, being allowed into this race is another question. Personally, I think his entry should have been ruled out as not qualified.