"Alleged Satoshis" are generally public, almost by definition. We would notice if they disappeared. We would also notice if the well-known Satoshi-associated wallets had any activity, which would be an unavoidable signal if any such kidnapping succeeded in finding the real one. Not everything is a deep mystery.
A lot of old timers in this space have been subject to kidnapping and ransom attacks, some real and some merely threatened, as well as more mundane phone porting and SWAT'ing. These don't make the news.
Then there are the other crypto people who have met grisly ends: Bob Lee and Li Chiming, as well as the suspicious deaths of John Forsyth, Tiantian Kullander, Vyacheslav Taran, and Park Mo. Not candidates for Satoshi, but it goes to show that "outing" potential Satoshis is not a safe thing to do.
I know about them because I'm one of them. (This is a pseudonymous account, but I've been a bitcoin developer since 2010, and subject to multiple personal attacks. Thankfully no kidnapping or ransom... yet.)
