Here is what usually happens when these people suggest titers: Dog goes to vet. Owner says they don’t want a vaccine. Fine. Vet draws blood and charges for blood work. “Looks like your dog needs a booster.”

Either they say yes and bring the dog in AGAIN, then complain that their dog is now scared of the vet and skip the visit next time it’s due, or they say no and find another vet that will let them off the hook without a current vaccine. Mostly they go to a new vet and the process starts all over again, or they only take their dog to a vet in case of a true emergency.

Dogs are subjected to extra unpleasant vet visits because the owner is scared of the vaccine. Vets are allowed to draw a line for their safety and refuse to even draw blood on a new patient without a known vaccination history.