Once someone crosses a boundary with your kid, it's game over, whether they're family or not.
In a popular post on the AITA subreddit, a woman asked if she was wrong for cutting off her MIL after she cut her daughter's hair. She wrote:
I (39f) have a daughter Vihana (14f) with my husband Cole (39m). I'm South Asian and my husband and the rest of his family are white. My MIL, Connie had recently taken Vihana over for the weekend at her and my FIL, Tom (65m)'s house. They've had my daughter over for weekends and holiday stays before so I wasn't worried about anything happening.
Vihana seemed fine during our morning and nightly phone calls. Today, when my MIL dropped Vihana off, I was shocked to see her almost waist-length hair was now shoulder-length and that it was now straightened. Vihana has been determined to grow her hair out since she was in the sixth grade and has expressed no desire to straighten her normally curly hair before.
Vihana was crying and explained to me that her grandma had done this all herself, and lied to her that I gave my permission for my MIL to do this which is why she didn't mention it when we talked. Needless to say, I was pissed and after comforting my daughter, I told Cole what happened and we talked for an hour about what we should do about the situation.
We eventually came to the agreement that my MIL wouldn't be seeing Vihana alone until she learned to respect Vihana's boundaries. We ended up calling my FIL to see if he had anything to do with this, and he was horrified when we explained things to him and said that my MIL gave him the same lie about getting my permission to do this.
My FIL apologized profusely before hanging up, and I ended up sending a text to my MIL about how she was unable to see Vihana alone until she apologized for what she did and learned to respect Vihana's boundaries. It was quiet for a while until Cole and I started getting bombarded with texts from both my MIL and my SIL, Lucy.
My MIL is furious with me for trying to keep her away from her granddaughter, and for telling my FIL what happened because he's now staying in a hotel and contemplating their marriage.
Lucy is calling me a b#$ch for what I did and saying it wasn't a crime for my MIL to act in my daughter's best interest even if she went behind my back, because clearly I wasn't going to take care of her.
It wasn't your daughter's best interest. It actively when against her desires and her body autonomy. She lied to your daughter, to her husband, and actively did something she clearly knew was wrong. Well, she gets to pay the price. She's one of those people who doesn't believe any boundaries are meant for her and she doesn't have to respect them.
And telling your daughter that you approved...that's just disgusting. She's trying to undermine your relationship. Wow. NTA.
NTA. The lying about having your permission is what really gets me. Lying to her granddaughter, lying to her husband...what did she expect to happen? I highly doubt that your FIL is contemplating their marriage because of this, it's more likely that he tried to confront her about it and she blew up, or maybe it's the straw that broke the camel's back.
NTA. This is actually assault, she cut a minor's hair without permission. Report it to the police.
NTA. Consider adding your SIL into the list of people not allowed near your daughter too.
NTA, and it is abhorrent the level of disrespect your MIL showed your daughter and you. Now your SIL is jumping onto the wrong side. I would absolutely go No Contact with MIL and SIL until they are ready to apologize and acknowledge their mistakes. That is if your daughter will accept the apology.
Clearly, OP is NTA - here MIL is fully ab*sive.