If you cash out by bitcoins at a casino and the casino doesn't add enough fees for fast confirmation. If the price of bitcoin drops a lot. Should the casino be held responsible for the price differences in which you cashed out at and the current loss in btc prices?
I think yes but no any casino will be willing to take this responsibility. They only update their system when someone report this issue to them and what best users can do is to either wait for confirmation or use tx accelerator services like viabtc tx accelerator to get faster confirmation.
I think theres no connection of an accelerator regarding on the thing that OP mention. It may push the transaction but on owners/players own expense which definitely means that casinos wont really bother at all on refunding you on what you have spent. If the price goes up then they wont claim on the excess bitcoin you do have since they do always base on bitcoins rate no matter how volatile is the price is.