I think this is the key, the great power of signing your notes comes with great responsibility. We are shifting from the old paternalistic model of 'oh, you've forgotten your password? Don't worry, sweetie, we'll fix it for you, now go back to playing with your friends in "our" (walled) garden' to being the sole responsible party for your identity and actions. For sure, we are humans and therefore we err, but the key, as you pointed out here, is that users have the possibility to contemplate their actions and responsibly take a step back before they get broadcasted and spiral out of control, rather than acting irresponsibly and hoping everyone else will cover for your lack of accountability