I'm speculating wildly of course. We'd have to define what powers the Silmaril gave its holder, which I think might be quite tricky. But Thingol was apparently impressed by the fact that it was so, and considered his demand on Beren fulfilled. Of course he was the victim of his own unfortunate wording. But maybe the power of the One Ring was controlled by equally unfornately worded spells. Did Sauron think of adding a sub-clause to the spell stating that the finger had to attached to the bearer.

well, I suppose the same thing happened to Sauron too when he had his own finger cut off. Maybe he somehow 'wished' or controlled Isildur's subsequent death? In which case he didn't really lose the Ring until the flesh had rotted away in the Anduin.

This is a crackpot theory, I don't deny it, but it's worth a thought.