when I visited the Nautilus with some friends cellphones were just becoming comercially viable for the (well off) general public. Post brick, but they were still unusual. it was very rare to see them. So we come up from below decks and the friend gets a call on cellphone. OMG, actual reception! and starts jabbering into the cellphone in Russian. The guy on duty was giving him quite the look over it. he eventually decided he was just a tourist.

(it was his mom on the phone, so I suspect the tone made it fairly clear it was Mom)