Apple could try, but there's no reason they couldn't give the talk. Apple could patch the problem, that's a possibility. Why would anyone get sued? It's completely legal for a security researcher to test their own devices. These guys aren't exploiting people on a widespread basis, they're researchers presenting a new exploit. That's what the Black Hat conference is all about.
I don't know anything about the law, I just assumed that this kind of thing isn't something big companies really want being spread around and I've gotten used to living in a world where legal action or at least the threat of it is a default response. Good to hear it's not like that in this situation!
