It is not about CH taking the btc, it's about the solution.
I think Davids solution is certainly a way to correct this. But I don't agree.
Why: because it is impossible for a third party to be 100% sure it is CH's account.
Without the solution it's 100% sure many people will get scammed. With the solution there's 0.1%* chance someone will get scammed.
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* If we estimate the chance CH didn't sell the seed is 99.9%