Do we need some kind of card to carry or a register - like an organ donor card, to say that under no circumstances do I or would I ever consent to violent sex?
Like you can register to 'do not resuscitate' I would register that I blanket do not ever consent to being strangled or beaten or role-playing rape.
Black and white, ahead of time. So that when I again tell them in court, I can point back and say look, I said this, I signed this, in front of a notary, it agrees with what I'm saying now. Convict the bastard.