I would get this checked but these might be some guidelines: 1) Is your backyard adequately fenced off? If so, and they are coming over the fence, then you cannot be held liable, as they have entered your home illegally. If, however, it is not fenced off, and they are coming onto your land illegally, you may be liable. Same for a pool. 2)If they are entering your yard while you are not there, they are trespassing. Any injuries they get there are while they are trespassing. If parents threatened action, you could threaten counter action. It is the parents' repsonsibility to make sure that their children are on their property and not on someone else's without permission My sister had an issue with her dog biting a child a number of years ago. The dog was tethered in a friend's yard, near the front door. Children from a neighbouring house entered the yard without permission, and approached the dog. What happened next is unclear, but the children did have food in their hands. Anyway the dog bit a child on the face. However, my sister was found not guilty because the dog had been adequately restrained, and the children were unsupervised and illegally on the neighbour's property. However, as I said, you should talk it out with legal advisers because you do not want to be caught unawares.

This is one of those things where the answer depends very much on which jurisdiction you live in. In some jurisdictions, you can be held liable if you have an 'attractive nuisance' on your property, in other words, if you have something that will attract children in spite of their caregiver's best attempts to keep them confined to their own home property. Go to your local legal advice clinic and find out what the laws are where you live.

This is something on which you should check with someone who practices law in your area. Unfortunately, common sense does not apply to situations such as this. Some time ago I wrote a research paper on this sort of thing for one of my college classes. In it I listed a number of what I considered to be be outrageous civil cases. One of these cases involved a would be burglar. He admitted that he was wondering around a house, at night with the intent to break in and steal from the own. Because it was dark, he did not see the hole in the back yard as he was sneaking around and fell in to it injuring himself. This burglar then sued the home owner and won a hefty settlement despite the fact that he admitted to trespassing with the intent to burgle. So, keeping this in mind, you should check with a lawyer in your area to find out just what your liability would with the trampoline.