It was possible, only 20 years ago, for Richard Ellis to write that confusion of "sea serpents" and giant squids was made all the more possible by the fact that no one alive had ever seen a live giant squid for certain, so how they would look and act near the surface was open to question. Sightings of giant squid are still extremely rare - I count one confirmed underwater sighting by humans and two videos, plus a few instances of catches on the surface - so they are still newsworthy.
Here's a new one, a catch made by a Japanese fisherman who got a rope on the squid and hauled it in still alive (it died shortly thereafter). It was about 4m long and would have been twice that if the long tentacles had been intact. Mr. Okamoto is a shell diver who had the weirdly unsettling experience of a having a giant squid swim above him - as in, between an unarmed human and the nice normal world of the surface. Fortunately, it apparently was in no shape to cause trouble.
Fatal interactions between humans and giant squid (fatal to the human, that is), are stuff of legend, but may have happened, especially in a World War II incident in the Atlantic, where survivors reported that people had been pulled from makeshift rafts: one fellow turned up on the old Arthur C. Clarke's Mysterious World TV show to display dime-sized scars on his leg.
So giant squid are still mysterious. Good for them :)