[jfriedly]

If sudo works the same way on Mac's as it does on Linux, then anyone in the sudoers file could give a rogue application root access.

[hackermom]

It does, and, the only user there, by default, is the first user of the system - the administrator. Not all people use this as their main user.

[mahyarm]

By default, most do, and what happens by default is what matters to virus writers.