The Mansons and the Waynes always had a...rocky relationship. Starting with Alfred facing off against Ida on the battlefield during his time in the British secret service. And cursing when the girl scurried out of his sight.
Although they no longer wanted to kill each other (maybe, they had children to take care of), their rivalry prevailed, and they could start fighting over anything. It was one of the reasons Ida attended to the Wayne Gala and only the Wayne gala. Just to upset the butler.
And this didn't just stay with them, Pamela HATED Bruce Wayne (and the feeling was mutual). They attended galas since they were kids and he was the most fucking annoying person she knew. She couldn't believe how he fooled everyone with "the playboy Brucie", he was obnoxious. And smarter than people gave him credit for. (Also, Pamela was pretty sure he was gay anyway)
Sam didn't want to follow this family tradition but when Damian Wayne tried to stab her with a cooking knife (after she kindly gave him an advice, taking responsibility as the eldest between them), the war begun, again.
Danny started attending those galas only to see things explode after being told this piece of information by Sam. The entire Manson family knew about it but the Waynes had no idea why the Masters heir was there. He even brought popcorn!