Personally, I'd guess that I wouldn't consider it "stealing" an identity if it were evenly trained off a couple of individuals. But it is a weird case ethically. Can I just train a model off of my favourite bloggers' works and tweets, and release a tweetbot replying to stuff I think would be topical? I've basically done that, but not hooked it up to Twitter, and I think that might be fine as long as the model is private. But this is certainly thorny ground.
