https://news.ycombinator.com/item?id=11696750

Suffice to say, the real point is whether people can compromise his apps with something that would harm their computer. So, let's rephrase your question, "What's the difference between convincing him to post a challenge string on his website and convincing him to arbitrarily modify code of apps he distributes to users?" Obviously, a huge difference unless he's a complete idiot.