Well, many people when faced with a question from the computer will be to try to ignore it for as long as possible, that's not ideal either. Opt-out auto-update feels like the right way for consumer software, opt-in auto-update for professional software, like developer tools.
For professional (and especially tech-oriented) software I think there’s more leeway to ask the user. Prompt on install/first run would probably strike a better balance than opt-in.
