Exactly this. Not to mention some vets that will do unecessary proceedures to get money. I had a vet once that recommended a proceedure, assured me that I could set up a payment plan to affort it (to the tune of 2 thousand dollars), then held my cats hostage until I paid all of it. Up front.I would love to believe this, but vets in my area vary substantially in terms of whether they perform convenience/cosmetic surgeries and convenience euthanasias. If one vet refuses to put down your cat because you're moving away or just plain tired of orange cats and want a gray one, you need only drive down the road where another will do it.
Vets are people, and as people, are different from person to person in their ethics.