I think the trick here is that Facebook is not inherently in charge of transactions, each validator is. Meaning, each validator will have their own efforts to m

I think the trick here is that Facebook is not inherently in charge of transactions, each validator is. Meaning, each validator will have their own efforts to make sure nobody pushing transactions on their node is doing crime (and/or that their identity is known so it can be forwarded to police when linked with crime). In practice what this probably means is that each validator will require a lot of personal information tied to each public key before accepting transactions from that public key. In other words, I would wait until/if someone trustworthy partners as a Libra node (e.g. my bank who already knows my financial history) until I sign up to give it a shot.