Thank you all for participating this discussion.
Let me explain why I think it's important to have a key recovery mechanism with BTC. And I understand all privacy concerns, that's why, I see all proposal here as optional, but most likely suitable for large scale BTC adoption.
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There's saying "prevention is better than cure". So IMO people could just take more time to backup their wallet file or recovery words. In addition, you could either encrypt the recovery words or split it using split before you place it on someone's else to reduce amount of trust needed.