Assuming for the sake of discussion that this is only given to addicts so they can break their addiction then I don't think that would be any more of a strain on hospitals than preexisting exceptions demanding special consideration, such as allergies and natural treatment resistance. It's already common for people to know when they can't be administered a given medication and to inform first responders and doctors. It's also already common for that information to sometimes not be provided and for a patient's treatment to fail. Unfortunate, yes. But also, we weigh these sorts of cost-benefit considerations all the time. It comes with the territory of living in a society. The possibility of that occasional misfortune doesn't seem to outweigh the benefit of helping millions and potentially ending the fentanyl crisis.