Being polite or ''nice'' means they don't have any fear or respect for you. The message that something is wrong needs to be driven home and frankly they can be a bit slow as well as lacking in social graces. My approach would be to walk out there calmly and tell them confidently and without emotion that I can either 1. drag them around to their parents, 2. call the guards , 3. take their ball away etc and that they can choose which one they want. It works for me. Now I don't advise this for everyone or for a lone female especially. The ability to make them believe you belong there and they dont without tripping up is a special talent. Not everyone is going to be strong enough or gutsy enough to do it in which case I suggest having the company of friends with you at the time. If you show any weak emotions, even anger or humanity their sociopathic nature can take advantage of it. The problem I would have with befriending someone whos already done something bad to you or your property is that trying to act like what they did doesn't bother you and isnt wrong is selling your own values out. Its dishonest and its an act of total submission/surrender. If it comes to that point then you've already lost more than some damaged property. This will give these kids the notion of ''its ok we can break somebody elses window and he will befriend us.'' Plus I wouldnt want to be mixing socially with feral kids who dont share my values and I wouldnt want them calling around to my front door like we were friends. I would want them to feck off basically. Being nice to a bully doesnt work. A bully only respects strength.