Lets imagine the ETFs claim to hold 1 million bitcoin. today. Now lets say in 5 years they claim to hold 5 million bitcoin, but really only hold 2.5 million. How will we prove how many coins the ETFs hold? Until the ETFs subject themselves to proof of reserves (which they will of course refuse as they do today), they can claim whatever they want. Now, if they claim to have 22 million bitcoin, that is a different story. But they can dilute the market substantially without getting to obscene numbers like that, just playing in the sub 10 million bitcoin paper game. I'm not saying this is happening. But it could. And we would be just as vulnerable to it as gold.