Can the casino change a deck or sequence of numbers (in roulette, for example) in the middle of a game?
That is categorically impossible. After the deck or sequence of numbers is created, you are given its checksum. At the end of play, you can confirm whether or not the checksum that was given to you corresponds with the deck or sequence of numbers that were displayed during the game. If even a single number were changed during the game, the checksum would change so completely that you would notice immediately.