However, there are several safety guards that common individuals can partake of.
I use Ubuntu on my home computer with other security measures.
My laptop has US gummit grade Norton on it.
I know that this doesn't preclude a dark possibility, however, it does greatly reduce the likely-hood.
But, I doubt the individual that had the friend put porn on his computer really qualifies as “having taken measures” to minimize these possibilities.
So is incompetence or carelessness in IT security now a crime in your eyes?
I’m quite careless when doing research for books I write. Why? Because I use Ghost and can restore my computer to proper use in under 10 minutes.
Those of us who know how to fix them don’t crap at the possibility of an infection. And antivirus is far from 100%.
Now, I don’t doubt the man was deliberately seeking kids porn, but you have to prove intent, not simply exposure. If exposure alone is enough, you’d have to arrest the judge, jury, and investigators for viewing the pictures.