The case of the 500-mile email
Fascinating, although I'm guessing the author isn't an electrical engineer, because for me, the timeout on the messages would have been the absolute first thing that I checked as soon as I'd confirmed the 500 mile limit.  Although that's probably because I spent a certain amount of time at the start of my career detecting faults in fibre optic and copper installations using reflectometers  to work out how far down the line the problem was...