Neighbor's kids continue to come in our yard (uninvited) to jump on our trampoline. Looking for suggestions on how to handle this.

New neighbors moved into the house next door towards the end of the summer. They have 4 boys between the ages of 7 and 15.I have 3 boys. My younger two are around the same ages as her older two, but my boys don't like these kids. They hung out when the neighbors first moved in, but decided to distance themselves from the boys. They are not friends.Anyway, the neighbor boys have been coming into our yard to jump on our trampoline. They usually do it really late at night or really early in the morning. They have also done it in the middle of the day when my boys weren't back there.I have spoken to the parents, but they both are of the "boys will be boys" mindset and don't think it is a big deal. I really don't know what else to do. There are so many reasons for not wanting these boys in backyard.Note: Before anyone says it, WE HAVE A FENCE. It's 8 feet tall. The boys climb the tree in their yard to hop over the fence. via /r/Parenting http://ift.tt/2jqI7bt