Is that relevant to people who might do so? Not clear what your point is at all.
People who look after pets professionally while owners go away including catteries and kennels insist on vaccinations.
If you have a relative or friend who does it for you and has no pet of their own they might not think of vacs.
Of course it's important to keep their vaccinations up to date, lung worm and cat flu are not pleasant illnesses to behold. We don't usually catch things from pets, that's zoonosis and such illnesses few and far between. Also fleas carry tapeworms so good idea to use preventative stuff monthly, same with anti worm meds - kids can catch the worms. I always did that with my animals (don't have any pets now) and they kept well and free from parasites while they lived. Nothing to do with sentimentality, just normal caring and precautionary.