This is a good reason to never log in as Administrator. Once your new Mac has been configured the way you like it, it's actually quite rare you need admin privileges; typical examples are when installing a full-blown third party app, performing a system update, or if there's a problem with the print queue.

I never enter my admin password for a small "free" app, plugin, etc. Rather, I copy its Application icon to my home directory instead of the systemwide App folder. (If I'm really concerned about a new app, I will try it under the Guest account.) Only apps obtained/purchased directly from reputable third parties (e.g. Lightroom, OpenOffice) will get my admin password.

I've ensured my family's Macs are setup this way too. At the very least, it makes them think twice before keying in the admin password. Now that Apple has surpassed Microsoft in market cap, and Google is phasing out all its Windows desktops, OSX becomes a bigger target.

If your local user account is compromised, it's easy to reboot, login as Admin, delete it, and restore just your documents from a backup, without affecting the rest of the machine or other users.

Barry.