I would definitely have to agree with Oz on this one. Kink is just something that's a bit out of the "norm." But when put in context of DS, it changes completely.

Take, for example, any kind of fetish. Let's use latex just for grins and giggles. If you like to be completely covered in latex when you're having sex, then it's just simply a kink. But, the moment that some sort of power exchange (ie. Domination, submission, surrender) happens, then it becomes BDSM lifestyle.

I think, perhaps, even though it's a kink, any kind of bondage would be lifestyle related.