Churchill Downs has a very strong interest in fighting this as hard as possible, regardless of whether or not the stewards screwed up.

Here's just one reason: Imagine a class-action lawsuit by holders of Maximum Security tickets (WPS and all the different exotics).

If successful in overturning long-established practice, it would be a huge financial blow to Churchill Downs AND could change the industry. (For instance, no more disqualifications a month or two down the road for use of illegal drugs while NOT reimbursing the bettors.)