The people in question are a retired electrician and his wife. The electrician had worked on Pablo Picasso’s place in the last years of his life, and according to the electrician, Picasso’s wife had given him some paintings after Picasso’s death in appreciation for the work he had done. The couple put them in their garage and ignored them until recently, when they decided to have them appraised. Picasso’s heirs heard about this and brought them to court to reclaim the artwork for the family, and the court ruled in the family’s favor. It ruled that the couple had illicitly procured these artworks and gave them a suspended sentence. See here.
First, it would be ridiculous to assume that this couple did this for gain since they did nothing with them for forty years. People steal artwork because (1) they want to resell it and make a lot of money, or (2) they actually like the artwork in question, so they intend to display it in their home where they can look at it as often as possible. This couple waited forty years before trying to resell them, and they didn’t display the works, either. Probably, then, the works were given to them out of gratitude, and the couple had no real interest in them. Also, it’s probable that after he retired, they may have been short on money, so they thought about selling off the artworks to help pay some expenses. Instead, the whole business blew up in their faces.
Second, let me point out that artwork is often given away, and there is no certificate given along with the object proving that the recipient has received the object in good faith. Here are two stories of this sort of thing.
The first was told by my father-in-law, Boris. Boris had a nasty war, as the saying goes. He was at Omaha Beach, but survived, and helped liberate Paris. While at a restaurant, a waitress asked him and his buddies if they wanted to go see an artist’s studio. No one else was interested, but Boris persuaded them all to take this excursion. They were brought to a second-story room where there was a little old man chain-smoking surrounded by a lot of what Boris thought were bad paintings. When the old man saw the soldiers, he asked if any had any cigarettes, and Boris, who didn’t smoke, gave him not just a cigarette or even a pack, but a whole carton. The artist was so overcome by this generosity that he offered Boris two paintings, which he declined. (He was more interested in impressing the waitress than anything else.) Later on he realized that the artist was Picasso.
Now suppose Boris had accepted those two paintings. I’m pretty sure that Picasso wasn’t going to give him a certificate stating he had the right to own those paintings. It was just a spur-of-the-moment gesture. Giving away paintings is what is sometimes done in the world of art, and it seems entirely plausible that the gift of Picasso’s artwork to the electrician and his wife was entirely legitimate.
Here is the second example. When my wife was a grad student at the University of Kansas, there was a moderately famous Chinese artist (Wan Qing Li) there since he had decided he wanted to be a scholar as well as an artist. See here. One day he asked my wife to do him a favor. He needed a fast translation into English of an essay he had written in Chinese because he was too busy to do it and it was scheduled for publication soon. He asked a Chinese student there to do a rough translation, and he asked my wife to polish it. I helped as well. He promised us a painting, which he gave us and which I am displaying below. Of course, we never got any certificate with it. It’s just our word against anyone else’s that the story I’ve told is what actually happened.