..... had said "Now you stop that, or I'll clip your ear!" to your 4yo? She knows perfectly well we don't believe in hitting children. And he wasn't doing anything really dreadful, he was fiddling with one of the cupboard doors. He stopped when I asked him to.
We stayed with her for four nights over Easter, and most of it was OK. She's not a horrible person and I don't hate her, but we are VERY different and I found it very stressful trying to manage the children my way on her territory IYSWIM.
She also said several times to my children "I think you've heard the word No more this week than you've ever heard it before!". The last time she said that to ds1 was at the dinner table in front of the whole family, and I replied without thinking "No actually, you'd be surprised - but it's much easier to discipline your children in your own home than in someone else's", and she replied "No, well actually it's easier not to bother at all". Which upset me a bit, because my children are quite well disciplined and well-behaved. I do say 'no' to them!!
So would you have argued/made a stink? Or would you just bite your tongue?