Can I get sued?

[tigwig]

I have posted on here before about problems with other kids playing on my dughter's trampoline. It is not in our garden as it is too big but on some land we own behind our garage which is next to our garden.
It is next to a approx 5ft wall which the kids must climb over then they walk around and unlock the coded security gate from the other side.
I spoke to my neighbour today about it and she said if one of them falls and gets injured they can sue me!
Is this true? I have told them about 20 times not to go on it but obviously I'm not in all the time to notice. I have also told them they are on private land but they take no notice.
Apart from take the trampoline down which I don't want to do as it is my daughter's, what else can I do? How could I be held liable when they are trespassing, climbing a wall that doesn't belong to me and opening what would be a locked security gate from the other side. I cannot lock the gate with a padlock as the neighbours also use it for access and they come over the wall anyway.

[dot.haukes]

I doubt you can be sued, as you say, you own the land and secure the entrance making it private property. Get disclaimers laminated and posted on both sides of the door saying that tresspassers use the trampoline at their own risk and any damage caused by unauthorised access and use will be sought.