My Horace has to have an ear amputated. It's an 'aggressive' attack on what's left of a mast cell tumor. So he'll get a crop on one ear. I CANNOT imagine that any of the surgeons at the vet-specialist practice would take a dog's ear for any reason other than to protect his health. They won't take the healthy ear. I'm not going to ask, but if I did I'm sure I'd get stink-eye and a curt refusal, as I would deserve from a responsible vet who respects the profession, the mission, and the patient over the human and the cheap dirty green dollars.
I personally feel that it is unnecessary & cruel. I feel that altering their ears or tail does not serve a medical purpose. When I adopted my dog, I had to sign a contract saying that I would never do those things to her. I would never plan to anyway. She looks great just the way she is!
I'm glad to find this thread because I was/am so confused. A guy came up to me on the street basically demanding that I cut my dog's ears. When I asked him nicely WHY I should cut my dog's ears he couldn't explain.