I am very torn about guide dogs. I know that they provide an important service, but what kinds of protection do they have?
I've heard of the Fidelco Guide Dog Foundation which supposedly doesn't allow the blind person to actually own the dog. This way, they can protect the dog and, in cases of abuse, take it back without any legal hassle. (I couldn't find confirmation on the site, but read about them in Healthy Pet magazine.)
I don't know how many guide dog groups do this though. It seems like the best approach to me though.