Back in the day, long, long ago, we did have an error report feature on the main page, where folks could report problems with quotes before they were solved. We'd receive about 50-100 incorrect error submissions a day from people who couldn't solve a puzzle and just assumed it was wrong. It just wasn't tenable.
At this point, our puzzle library has been played so thoroughly that I'd wager practically all of the major typos and mistakes have long since been remedied. A few still remain, undoubtedly, and we fix them as they're reported, but errors these days aren't as big of a problem as they were when we first started in 2007 with our original library of quotes.
While we're on the topic, we will be adding a significant number of new puzzles to the rotation shortly - probably the biggest influx of new quotes since we first started the site (about a 25% increase). These have been hand-selected and individually checked for errors.