*I think to me 'dub-con' is usually meant to imply that the party in question wants it on some level, or ends up enjoying it*

This makes sense to me. And is very helpful as I try to fill a prompt for someone at the spn kink meme. I honestly wasn't sure to classify as dub or non...but this is also my take on the issue - only much more succinct than I could have managed :)