I've been thinking about a possible legislative attack on coin joins and I'd like to get people's opinion on this.
What if a law was passed that said that if your bitcoin ever moves from the addresses linked to you, they'll assume it was spent or sold and you will be taxed on it. If you were just moving around your coins to fresh addresses (like in a coin join), you simply have to dox the new addresses and you won't be taxed.
This would be a great way to keep tabs on who owns which coins and how many. People would incentivized to not coin join if they bought from a KYC exchange. If KYC requirements were expanded to include centralized p2p exchanges and Bitcoin ATMs, then Bisq and the like would be the only way to get Bitcoin anonymously.