I'm surprised at how willing some people are to blame the victim. Yes, there are nearly always things that the victim could have done to reduce or avoid injury. However, people have limitations. They can't be hyper vigilant all the time. It's neither possible nor desirable, since this would cause a great deal of unneeded stress. Furthermore, if someone pays too much attention to one danger, then it's easy to miss others. In this case, I can imagine the girl trying to move quickly and quietly across the hall in order to not incur the displeasure of elders or busybodies. It would be impossible to focus on every single possible danger that was involved. It's true that they all knew that the wires were there, but this doesn't make it easier to avoid them because people will naturally get used to a hazard that they see all the time.
It's easy to look at a single situation and think if only the victim did this or that. Maybe the accident could have been avoided if the parent escorted the child across the hall (as has been actually suggested on this thread). However, it's absurd for a parent to hover over a child every time she moves a few feet. It also increases the chances that some random accident would occur. Suppose the parent tripped and fell on the child, I could see the same people who criticized the parents say if only the parent wasn't so overprotective this accident could have been avoided.
Since accidents are inevitable, it makes sense to pay attention to the potential causes of accidents and remove them if practical. This is where the Watchtower society is culpable. They know that the wires pose a hazard. They know and can expect that these wires will cause injuries on a regular basis for whatever reason. They could easily prevent this hazard, but deliberately chose not to. Yes, it happened in a local congregation, but it is the headquarters that directs and often insures the local congregations.
It is strange to suggest that you shouldn't sue if you have insurance to cover the accident. Why should the insurance company pay if someone else is legally liable? In this case it is another insurance company (run by the society) that is dodging responsibility. It seems close to insurance fraud when the society insures the congregations, but is notoriously stingy in paying damages and can use cult mind control techniques to prevent most claims from going through. If they get sued often enough, they might have to eventually start buying real insurance, like the rest of us.