content: It's actually a fantastic idea for just the reason you stated. This is a controlled environment with full disclosure of all discoveries. Any black eye that discovered vulnerabilities would create is far outweighed by the benefits of having the best and brightest find the weaknesses of your product so that you can rapidly address bugs and holes you didn't know about the day before. The vulnerabilities are already there and Tesla doesn't yet know about them. This is free (or prize supported) work being done by the best and the brightest for the benefit of Tesla and its customers. It's a huge boon overall and really shows how much Elon Musk "gets it" when it comes to technology strategies.