Security is all about end user education. You can make a browser as dummy proof as you want, but if a user is click happy and just clicks yes to everything, then all the security built into a browser wont help. Firefox has had its share of security exploits and that, in my opinion, has blown away the illusion that most firefox evangelists had about firefox being impervious to such attacks (buffer overflows, underruns, etc). I think more time should be spent educating the end users about security as opposed to trying to dummy proof (from a security standpoint) the software (in this case, a browser).
