I'd do something with clear mono string or something that they could trip on when they ran off.
As fun as that sounds it sounds like some work. Going to try and talk to the kids/parents about it but we are not far from getting the police involved to try and scare something into them but we would probably need proof it was them to do that so we will be investing in a wifi camera before then.
Last time they were hiding behind a neighbors van. This time they were riding around on their bikes and I noticed bike tracks through the grass.