What I see as a problem is that it legitimizes the idea of a message in a browser telling you that your computer is infected with malware. A rule of thumb I've

What I see as a problem is that it legitimizes the idea of a message in a browser telling you that your computer is infected with malware. A rule of thumb I've given to the confused class of users is that only antivirus programs or Windows will tell you something like this, and that if a browser window pops up and claims to be running a scan it's lying. Now Google is screwing that all up.