Good question.
i voted no because i can't ever imagine myself initiating a scene in an obvious sense. i'm not sure if this is because of past experiences of both BDSM and vanilla in that i hate the idea of being rejected, and i suspect this is something which may change over time, but right now, no, i wouldn't initiate it.
Having said that, i'm not sure one has to initiate it in an official capacity to be actually initiating it...i may well , sort of, imply that i'm up for it or give him a look or something (does that make any sense?).
i know some dominants very much like their subs to be involved with what takes place, but i still think a sub forcefully initiating a scene seems a little odd. i think there are other ways to contribute to what takes place. i think discussion after a scene is always a good idea in that regard as is ongoing casual chats about fantasies etc..you can gauge a great deal about a person from what they will say in a relaxed setting when they least think you're listening.
sl