To encourage care, I highlight cases that have turned on punctuation or the high cost that can result from a typo. Winning cases and saving money tends to get their attention.
There is a post on Mental Floss that discusses some interesting and expensive examples of costly typos..
- A missing hyphen in a code cost NASA $80 million
- A spelling mistake in an eBay ad cost the seller
These examples are good classroom fodder to make a lecture on punctuation and grammar just a little more interesting.