They're not actually playing petty games with each other. Helena just kissed Dick as a distraction--which made sense as she's his date and they were listening to people nearby. She didn't realize that Babs was listening. The way I read it Babs wasn't angry, Helena just wished she hadn't done that because it was too reminiscent of the time Helena and Dick slept together and she knows Dick is Babs' ex (and Babs was not thrilled when they slept together). It's not that Babs is jealous or Helena was trying to piss her off, it's just that if she knew Babs was an audience for what she was doing she probably would have found another way because she wouldn't want to make out with him with an audience of Babs.