Play Place Etiquette

The girls and I decided to brave the mall this afternoon for some shopping and play time. We quickly finished our shopping and headed to the play place. The girls were both thrilled to get to play on the toys and run around a bit. We were not there 2 minutes and another child decided to follow my kids around (quite close) and do everthing they did. They wanted to play in the car (with room for 2) and she somehow squeezed her body in there too (squishing LittleZabba in the process). So they moved on to another activity and she was close behind. This continued for a few minutes, with BigZabba getting really frustrated, and then it turned into the child pushing her way past them to get to the toy first. What do you do? At one point I (in my I'm a really nice Mommy voice) asked her to share the toys and let them have their turn first, but that didn't work. Then, in a tiny bit louder but still nice Mommy voice, I asked her to stop pushing, but that really didn't work either. There was a man there with her, but he clearly wasn't really watching her. BigZabba was in the middle of the play place and she literally threw her hands in the air in disgust as the girl pushed her way onto the ladybug that Big & LittleZabba were trying to play on.

At what point should I have asked him to control his daughter, or whoever she was? It really was pointless to stay because they were not enjoying their play time, they were only trying to get away from the "rude girl" as BigZabba named her. So we packed up and wouldn't you know it, the second we stood up to leave, they left too. Perfect timing!