Why don't they just try to ignore the canoe and let it go by. The people might not recognize Clark Kent and some lady as the people on the beach. Sure, everyone knows what Clark Kent looks like, but they might not get close enough or pay enough attention to notice. Even if they do, so what. Superman was seen with a woman on a beach. That does not mean overly much. It is not like he is keeping his relationship with Lois secret. They draw more attention by running than staying.
