I would do that if I was more confident that Maddy was spanked, or if I suspected something really serious. My wife and I have both told Maddy a bunch of times that the teachers at her school are not allowed to spank her. I'm very confident that we will hear about it if she is spanked.
But I honestly don't know if it happened. I really don't. And while nothing is more precious than my child, I am cognizant of the fact that this lady's career is very very important to her, and the director's daycare is very important to her. And the last thing they need is an overreaction, making all the other parents paranoid that something's going on, etc. For now, this is enough for me. If I was sure it happened, or I suspected something worse, or if I thought that the director was not taking it seriously, I would go further. But this is enough for now.
I hear ya schmokes. I'm not saying grab a torch and dust off your pitchfork. I'm just suggesting you find out.
You just said "
But I honestly don't know if it happened. I really don't." You do still wonder though, right?
I understand that you don't want to hurt the teacher or director. There are ways to approach people without shaking the hive. Maybe your circumstances are different, but my wife and I have always made a point to be friendly with our kids' teachers and directors/principals/owners. Same with the other parents. We see them more than some family members!
My suggestion is not to confront and accuse the teacher, but more so to approach with a smile and ask simply, "Hey,

what happened the other day with Maddy?

"
I do hope that this was either a child's embellishment or a teacher's
one time lapse in judgment.