That said - I've seen quite a few toddlers with bangs (fringes) so long that it was apparent that the hair was often in their eyes, and they seemed/looked uncomfortable, and I wondered why the parents hadn't done anything about it. IMO if the grandparents had said "we're sorry, we didn't mean to upset you but her hair was really in her eyes"........well, that's not great, but I wouldn't throw them under the "you will never see your grandchildren again" bus, either.Because we are waiting for them to grow out, so they'll be long enough to put in a ponytail, and then we'll NEVER have the "hair in the face" problem again!!!!!!!!!
We were about .75" away from that point when my MIL decided to get 4yo DD's bangs cut. I was so mad! It had taken a long time to get to that point, and DD and I had JUST said, "Pretty soon you can have it all back in the ponytail!"
All our waiting, all her patience--throw right out the window.
I gave up--I was not willing to go through that again. So we stuck with bangs. Which meant that every 5 weeks I had to take her to get a haircut. And pay for it (because getting bangs right is too hard to DIY). Instead of simply being able to trim the ends of her hair myself every 3 months or so.
I didn't throw Grandma under the "never see my child again" bus, but I did make it clear that I wasn't happy. (I'm not sure why DD didn't say anything, but she was a very biddable child, so shee probably figured Grandma knew best--or didn't realize quite what was happening.)
I was really pissed off.
There is a rule, and grandparents should know it: No Grandparent May Get a Grandchild's Hair Cut Without the Express, Direct, and Wholehearted Approval of the Mother. (No, Not Even Dads Are Allowed to Permit This--Only Moms.)
The lying is the bad part, because it sure indicates that she KNEW she shouldn't have done it.
I think if I were in this situation, I'd simply cut off all contact and conversation for a while. I'd let everything cool down. If contact did happen for some reason, I'd be Teflon--vague, "oh no we're just so busy."
And then after about two weeks of radio silence, I'd say to my mother, "I'm upset with the fact that you got my daughter's hair cut without my permission. The logistics of managing her hair are MY problem; and you stepped over the line. And you KNOW you were over the line, because when you were asked about it, you flat-out lied.
"And I'm also mad that you lied. Really mad. You owe both us parents an apology for usurping our parental authority; for making our lives more difficult because now we have to deal with the hair mess; and for lying to our faces about it."