Dave, someone touching a hot circuit isn't shorting out a circuit, they are electrocuting themselves. So anyone who has had an electrical shock hasn't caused a short in a circuit because people are not circuits. Most people 'explain' electrical problems as 'this short' or 'that short', when in reality they have absolutely no idea what is wrong but hope they can either convince someone to part with a whole lot of money, or just get them out the door because no one wants to have anyone think they do not know something about the reason they brought their car to them. Most of the time when circuits do not function, it is because of an 'open'. This open usually involves a broken or loose connection. The hardest ones (opens) are buried in multiconnected connectors that may flex and 'loosen'. The absolute worst ones are those buried in areas that require a whole lot of disassembly to access. Where 'chaffing' occurs, a sharp conductive object repeatedly rubs along one or more wires and the inner conductor sometimes touches something grounded (or in the case where the sharp metal item isn't grounded, completes a circuit with another wire when that wire gets cut to its conductor). In the case where mice chew into the wires, the damage can be so expensive as to not be economically feasible to repair. This could be when a high current source (12v) gets 'shorted' to multiple sensor/computer data wires and it 'fries' many components before the current actually exceeds the circuits fuse rating. Anyway, if this was too long, I hope you didn't fall asleep. Does it help any though?