The two people who said nono, gave the following reasons:
- Security concern
- Ethically unpleasant
One alternative that would take care of both of them: override codeblock behaviour to select-all text within that codeblock when double-clicked.
This way, there is no additional button to be ethically unpleasant; and since you have to click CTRL+Cpress CTRL+C manually, it is not a security concern.