We had a retarded/deaf kid in our neighborhood. For some reason, he decided to hang out at our house. He was a huge kid who I was told was inappropriate with young girls. He followed my daughter and her friends (who was MUCH younger). Maybe he was just lonely. We were always nice to him. My husband even loaned him money from time to time but we finally had to dissuade him from coming over. I never knew if the accusations were true about him, but couldn't take the chance.
I still think of that kid and what happened to him. He had nowhere to go and nothing to do. Sad.
Likewise, if it seems rude or "Ska8Nazi" to swear out a complaint about a teen you've never seen before in your life trespassing on your property twice, that's life.
I'd rather be safe than cool.