Answer duplication checks apparently only check if an answer is a duplicate of the answerer's own previous answers. Well, that's fine 25% of the time, when it's a spammer.
However, we have a decently large problem with plagiarism. I've seen many instances this week where a user copies, verbatim, another answer. If it wasn't for our superawesome kewl user base, we'd never know.
Can we open up dupe checking for all users' answers? I know, I know. Lots of cycles. Maybe do it only for low rep users? (pfft, under 10k? Noob.) And only for new answers?
Look at what the current state of dupe checking does to maudlin monkey. Look.
Maudlin monkey is maudlined by plagiarism. Let's unmaudlin him.