This pet peeve is actually less about the brat than it is about the parent of said brat. I mean the parent that pretends like their bratty child just doesn't exist. You know this person. They're in the aisle of Target, at the next table in a restaurant, in the movie theatre (there is definitely a separate pet peeve on that one), they are nearly everywhere you go.
Picture this: The child is doing something completely beyond the realm of public acceptance. This includes a full range of possibilities, from small scale screaming to a full fledged grand mall temper tantrum. And the parent, yes - the one person truly responsible for the child, is doing an Oscar worthy performance of pretending that the child is not even there.
For instance, once I was at an Italian restaurant with some fellow diners (who shall remain unidentified) when a small child at our table, who had spent the evening under the wandering eye of a parent doing a stellar job of ignoring his presence, skewered a meatball in a moment of anger. He raised the meatball - not to his mouth, mind you, but to fling it across the restaurant where it landed squarely on the back of a woman wearing a white blazer. I am not making this up. And what happened? Nothing! The wandering eye glorified in looking intently between a bread stick and the crown molding.
The child is not going to disappear, no matter how much you ignore them.. Probably better to man up and admit to their presence - however bratty. It could be good for both of you (not to mention everyone else at Target).