It's easy to do the math and show this is nonsense. If a foot is a nanosecond for c, then 50ft difference is 50ns or about 10000x times smaller than the smalle

It's easy to do the math and show this is nonsense. If a foot is a nanosecond for c, then 50ft difference is 50ns or about 10000x times smaller than the smallest difference. Even if the speed in a cable was 1%c, it's still under the proposed threshold. Even so, try convincing my dad that it does not matter.