Man do you know how many instances exist? I hate this idea of trying to coordinate defederation across all bigger instances all at once. You have the option of migrating to an instance which is already defederated from them, or hosting your own instance and defederating from whoever you want. You can also mute them. Don’t come to a decentralized network with the expectation of imposing centralized decision making behaviour?
Nothing major. In my country when people are fired they are entitled to recieve some money based on how long they’ve been an employee. One time I overpaid a dude who was fired by some 5k USD or so (converting from my local currency) which is nothing major but my boss was pissed. Luckly I just called him and asked him nicely to return the extra money and he did without being rude or anything.
Edit: just as a comparison at the same company once one of our (corporate) clients sent us the payment for a service twice by mistake, some ~200k USD that they had to pay 1x we ended up recieving twice. By comparison 5k is nothing.