Nice Szabo: "Such confidence in Bitcoin is splendid, but a 94,500 BTC tx tempts fate. If recipient can make that much from reversing the tx, they can afford to run a 51% attack for more than 40 days. Big if & very visible, but security here depends more on trust & less on the protocol itself."
https://twitter.com/NickSzabo4/status/1169848736819773440