The sibling of a child in my daughter's class was constantly picking on and tormenting my 2 year old and his mother seemed obvious of the situation . I put up with it for 2 months before I said something to her(I felt I had no choice as I had to ask him everyday for 2 weeks to not do what he was doing to my toddlerI said all this in a controlled and polite way to him ) I was again very polite and stuck to the facts giving her a couple of examples of what he had been doing. She agreed there had been problems with behaviour and several other people had mentioned it as well.
Over the past few weeks she has been very offish and is now ignoring me if we meet whereas before she had been very friendly and chatty. Yesterday she told my daughter off because she would'nt give her child the toy she had found in the playground and was playing with. Looking back I don't think I would have done anything different but how does everyone else handle the playground politics I find them just as difficult as office politics tbh!