Would the coaches have reported it on their own if the logging coordinate had not caught it? Get caught, fess up; don't get caught, keep silent. Unfortunately, it is my opinion that this happens all over...opinion only.
The coaches should have looked at the calendar to see that it had changed the quiet period by one day from last year, however I truly do not believe the coaches knew they did it even after the fact until it was brought to their attention. If they were trying to hide it you don't put it in the recruiting log or you modify the date in the log by a day. Even though it is Wisconsin in this case I think it truly was a mistake.