“They love to mess with Bitcoin and Ethereum the most,” said Dr. Wu. “The public has no idea what’s going on. It is a money printing press for them.”

Theoretically possible but very easy to prove or disprove. All we have to do is download a snapshot of Bitcoin blockchain on one computer, and disconnect it from network. After a few weeks write a script to compare the blockchain up until that point to the version in the latest.

Should be pretty easy, I might do this.