Right off, he told me he would just visit all the warez and porn sites that
are typically infested with viruses.

Some people will make any excuse to look at porn and get free software.
:)

Every year an off the shelf Ubuntu box beats both Vista and OS/X against
professional hackers. Computers are identical. The competition lasts three days
and Ubuntu has not been hacked yet. This competition has been held three years
running. OS/X usually falls on day one and Vista on day two. Both Vista and OS/X
have their usual protection and Ubuntu has its, which is just what comes
pre-installed with Ubuntu, none.

Can it happen? Sure, anything is possible. Is it likely to happen? No. Ubuntu
and most Linux distros are safe because of the way they are set-up. Some distros
are subject to abuse because they allow root logins and a few have virtually no
protection. I was surprised that Xandros on my eeePC did not ask for a password.
Ever. Scary. One look at this and I ditched it in favour of Ubuntu.