OK, she only took a little off - I didn't actually notice afterwards (daughter has curly hair, so it's less obvious). I only know because she told me later.
But it's the principle surely! It happened when my husband was visiting her without me, and he asked her to comb daughter's hair in the bath while he was putting our older child to bed - it's the easiest way to comb it with loads of conditioner, because of said curls.
MIL told me later she was encountering knots so she "nipped the ends off" - whatever that means. Actually I know where the tangles usually are, so I think in some places she must have cut off 1 or 2 cm.
You may say as I didn't notice, what's the problem, but it made me a little sad, because at that point my daughter had never had her hair cut, so the first time I cut it I wanted to keep a lock, so it would be a lock of her baby hair. As her hair was only about 2mm long when she was born, my MIL must have cut off her baby hair.
OK, I'm being a sentimental old fool about it, but that's the way I feel. I wanted to keep a lock of her original hair that she was born with and now I can't.
And putting that issue aside - the cheek of it anyway! I think if she couldn't be arsed to comb it properly, she should have said so. If we just keep cutting tangles out, daughter will end up looking like a scarecrow.