Actually, the prefix "Nomo-" is most likely derived from the Greek word "Nomos", meaning "Custom" or "Law".
Thus, "Nomophobia" means "Fear of [the] Law".
Whoever came up with that "no access to a cell phone" nonsense obviously knows nothing about etymology in general or the Greek language in particular.
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The mere fact that science may not yet adequately explain an object, event, or experience does not mean the immediate explanation should automatically default to a conspiratorial, extraterrestrial, paranormal, or supernatural cause.