I think all the big targets for this kind of thing have the legal or government muscle to get in your way? Millions of people usually don't agree on someone dying unless they're powerful.

It seems to me you underestimate the challenges of getting the money from such crypto scheme. A murderer would have to prove to the pot owner that they are, in fact, the real murderer and not someone pretending to be one to get the money. However, there’d be another actor trying to prove who the murderer is - the police. So, you’d practically have to dox yourself in order to get the money, or be able to have such a strong privacy system that a state actor cannot break it and identify you from your communications with the pot owner (lol). If you have such a strong cyber security system, you’re probably better off just selling it for $$$$$$ than muurdering randos.

But these problems would likely be self-resolving in most cases as the crypto pot owner would simply rug-pull everyone.

a tale as old as time. e.g., fixing a fight or a game