[pricechild]

Anecdotally, I've seen banks claim the reason for $something_bad was a virus on a chromebook.

Whether or not there's 'been a single case of fraud or loss attributed to "screen-scraping"', I believe most banks are more than happy to blame you by default and make it difficult/expensive to resolve.

[nailer]

Most people don't really distinguish between viruses and worms, and there's been worms on Unix systems before (hi RTM!)