1. Let the user specify `--remove-existing-chain=false` to avoid the prompt and fail if there's an existing chain. 2. Only prompt when interactive. Otherwise, _don't_ remove the chain by-default.
1. Let the user specify `--remove-existing-chain=false` to avoid the prompt and fail if there's an existing chain. 2. Only prompt when interactive. Otherwise, _don't_ remove the chain by-default.