With my husband if I have to say something, it's usually to say, "what can it hurt?" Sometimes he'll tell my daughter she can't do something because that's his default. If she's asking to do something it's generally reasonable. It's when she doesn't ask that it's trouble.
We're pretty easy going with how to deal with discrepancies. Just say it and move on. My husband has called me out before too. Usually the rare time we say anything it's warranted.
Danielle, Nick, Gigi ('08) and William ('11)