I would just mention it to Social Services and that it concerns you as it doesn't appear to be the usual play fight, squealing or crying, or just been repremanded punished crying or sobbing. At least that way if something untoward is going on you won't have to feel you sat back all this time and did nothing, on the other hand, if the poor woman does just have kids who just won't stop screaming, (my niece is the same, you would think she was being murdered when she is in fact having seriously bad tantrums and can often be heard from inside my car when I drive by the house!) if all is innocent the Social Services just turn up and ask if all is ok, they won't say its you and will say it was annonymous and once their fears have been alayed they will generally leave the poor woman alone to sort out her unruly child, (or tell her to buy earplugs!) My sister in law didn't get offended, though slightly embarrassed when one of her neighbours called in Social Services for her daughter, and the woman just sat there for five minutes and said to her, you poor thing, you have my complete sympathy, as niece in question, for just no apparent reason screamed at the top of her voice, do something though just in case, you never know.