f we wanted to get really philosophical, we could even widen the consent-theme to not sex related themes. canon even.
Like, angels need their vessels consent to use them as a meat-suit.
But is a YES from Dean or Sam, when given as a result of torture or because there is no other way to stop the end of the world really consent?

Thank you for bringing this up, this is the sort of question that leaves me pondering the 'good' and 'bad' motives of some of my favorite SPN characters on occasion.

Then again, making me think about these sorts of things is actually one of the reasons I like the show.

;)