The case of the 500-mile email is a pretty odd case with a fun fix. Can you share other stories where the actual fault was something unexpected.
Perhaps it can help others who have some strange problem that they just can't figure out.
I once heard of a serial port cable in a NY datacenter that kept getting unplugged. The punchline was it was being unplugged (and eventually cut!) by a union rep because the guy who had plugged it in (the owner and sysadmin of the equiment, visiting from another city) wasn't union labor.