Dog tattooing for ID was common -- BEFORE microchipping was developed. (OK, back in the dinnosaur age). Very few vets do it anymore, the microchip is more reliable. My friend's first Akita was tattooed. She lived 13 year, he had no dog for 2 years, then got his second Akita in May. He was talking about getting her tattooed, and I told him that was 'old school.' Sure enugh, when he took her to the vet for the spay, the vet explained he doesn't tatoo anymore, it is all microchipping.

I think it would be horrible to tattoo or pierce pet, especially for fashion. what, wre you going to have the tattoo removed when you don't like it anymore? (Some people do, so why not?) People know the pain they are facing having something "elective" done. Pets do not. If people are doing this, then I think someone should pass a law prohibiting it.