Need a different flying site...
First impression I had was a dad wanting some alone time but can see you definitely have an issue if the Trex gets out of control due to someone else messing around while you're airborne. If you have another person/parents that can give you some transportation to another location, that might be your only option as I have seen and experienced what a large size heli can do if getting out of your control. Not much you can do about the other kids unfortunately unless they find something else to catch their interest otherwise they might end up with a major injury needing many stitches or worse. Definitely respect your flying the 600 under the goggles but you definitely need a safe place to fly with your friend and no one messing with your gear while flying. Wish you the best of luck and keep it up, I've been addicted to flying fpv ever since the equipment came available.
Scott.