Trespass

We have a farm, and people try to take our produce away without letting us know. We decided to put up CCTV, and also that we will put up electrical fence which might shock any person trying to cross the fence, but not in such a way that would cause a very serious harm to the person. It would just be a small shock that will stop them from crossing the boundary. Some one tried to cross the boundary, and was shocked. They filed a case against us on the basis that these fences will cause imminent harm to anyone and that they were severely injured. My question here is, can we claim that they've tried to trespass and that was why they were shocked? We kept up those fences to prevent the ongoing trespassing. What will the outcome of the case turn out to be?