Even those that don't buy the etfs can put social pressure on the issuers to show proof of reserves. Ark has committed to it. Hopefully other issuers will as well which might put pressure on Blackrock to do so too but probably not. They would likely just have Coinbase attest to the bitcoin being there. 

grayruby

I'm wondering who is the community, though? MY community self custodies and wouldn't buy an etf to begin with. Their community is guys like Fred Kreuger who don't see anything wrong with paper bitcoin. Right now "they" only control <10% of bitcoin, but that may change as more of us sell out because of unimaginable profits over the years. 

siggy47

bitcoin

BlackRock's Paper Bitcoin

Proof of reserves should be the standard and the community should be shaming issuers into providing it. If they want to transact off chain then they should be proving they hold what they say they hold. 