I was not necessarily "opposed" to earrings on dogs if that is what you are into. I would not do it to mine, but who am I to judge others. If tail docking is not considered cruel then how can ear piercing be?
As far as magnetic earrings, I do think it would be hard to keep them on but I also would try to "judge" anyone who chose to put these on their dogs as long it isn't dangerous or hurt them in any way. I think it might be cute....I mean if necklaces are okay, why not earrings too?