I think that this trying to say that there are other dangers from physical injury or signal/other cables is a red herring. This thread is about infills using 3rd rail to deliver traction power to trains. Discussion in the thread has gone down a (perfectly reasonable) path discussing the H&S issues that the ORR, HSE & RSSB has with the undoubted risks from the very nature of 3rd rail systems. As others have said, the risks from signalling circuits are real but generally involving attempted theft of those cables whilst live, something that may be there even on an unelectrified track.
3rd rail presents an additional risk that doesn't exist on any other track, (wait for smartass comment about 4-rail track

). What's more, death from 3rd rail electrocution is killing people who are just walking alongside or across it, which although expressley prohibited, continues to be practiced by some for their personal convenience. The prohibition is entirely from a safety angle, because it is likely that some tresspassers do that for short cuts. The have no intention of damaging or stealing from the railway infrastructure, but the danger is ever present and cannot be removed. The comparison with those who go near OLE with fishing rods etc., is specious, as it is a potentially lethal activity, with no benefit like a time saving short cut, and perpetrators must be regarded as prime candidates for Darwin awards.