While I'm not the nominator, I'm inclined to put in a word for "Voyeurism" - voyeurism is a huge part of participating in BDSM community and events for many people. Arguably, public play is always partially about voyeurism/exhibitionism, and public play is kind of central to the BDSM community. Obviously, these things vary and so do people's own definitions--and ultimately, you're the mod!--but this one in particular stands out to me as strongly BDSM-relevant.