I guess the trick is re-reading them before the new one comes out, but… sheee-it. Who’s got that kinda time?
It’s a great idea for e-books, but given that I’ve discovered plenty of basic proof-reading errors in Butcher’s work, I think you’re right that they don’t care.
One thing I’ve noticed throughout the series, even into Skin Games, is the constant use of the word “jive” when he means “jibe”. I don’t know if we’re supposed to believe Harry doesn’t know the difference, or if Butcher thinks so many people mistaking one for the other on the internet means more people will understand “jive”, or if he and his editors have just overlooked this for 15 books. I’m leaning towards the last reason.