I'm sort of surprised that the developer tools have only recently become an attack vector (via social engineering). I'm not sure what can even really be done about it without seriously inconveniencing developers. Maybe making them disabled by default with an extra option to enable them would be enough to deter all but the most gullible of users?
Why not a separate package altogether? That way the Chrome team can focus on Chrome, and the Developer Tools team can focus on producing a high-quality website debugger.
This has been called the "dancing monkeys problem". People can really be manipulated into doing anything in order to see the dancing monkeys (even if they couldn't be convinced to do those things for constructive purposes).
IMHO you just can't save people from themselves, might as well stop trying and making my life harder.