While Luffy’s rubber biology prevents him from choking on bone-in steaks, the Straw Hat kitchen has rules for a reason. Sanji’s character arc revolves entirely around the sanctity of nutrition and food preparation. As the cook of the Thousand Sunny, Sanji is the only crew member who manages Luffy's bottomless hunger without letting the ship run out of provisions mid-voyage.
Sanji constructs locks on the Sunny's industrial refrigerator specifically to stop Luffy from raiding raw meats, frozen stocks, and inedible ingredients in the middle of the night. On multiple occasions, Luffy has eaten things that would kill anyone else, including poisonous fish skins (such as the Armored Stonefish outside Whole Cake Island). In that instance, Luffy collapsed not from choking on the scales, but from lethal marine toxins that required Reiju’s poison-siphoning intervention.
Sanji prepares high-density meals designed to fill Luffy quickly, using massive animal carcasses sourced from sea kings. The crew has long stopped worrying about Luffy choking on bones. When Nami, Usopp, or Chopper hit him with a frying pan at the dinner table, it isn't out of medical concern; it is sheer frustration that he is inhaling three days' worth of supplies in thirty seconds.
