I think I would have tried the "I surrender, I win" approach during this situation. As soon as they started messing with me, I would have let them go ahead of me. In fact, I'd get back in line after a couple of other parties pass by too. That's easier than putting up with them especially since you acknowledged their shenanigans which only makes them do it more.
I'm pretty good with kids. But there are times when my patience is thin thin thin and they bug the crud out of me. Especially at the park. I find it annoying that parents let their kids roam free in DL. But the reality is is that it's going to happen and I prepare myself for seeing/interacting with dinglecheese kids. I report unparented children shenanigans to CMs all the time. But then again, there are other kids who are well mannered out there (like I was when I was a kid) and they deserve credit where credit is due yaddah yaddah blah blah.