If someone knows how to spoof a useragent, they probably don't need virus protection anyways.
Yes but the underlying problem here is the your non-technical person on a Mac does need some sort of education or anti-virus. It's further building onto the illusions that Mac OS is invulnerable to viruses and spyware.
your non-technical person on a Mac does need some sort of education or anti-virus
Education yes, antivirus no. There are roughly zero active Mac viruses; the real threat is phishing.