I've only heard about KK (though I've heard A LOT). Based on that, I'm choosing No Way. That aside...
1. No. But if I did it wouldn't the vanilla crap that's just barely risky to get people talking the way the vast majority of sex tapes I hear about are (and make me think they were made to be released, no matter how much they pretend otherwise). I would make it a work of performance art guaranteed to shock and troll many people. Otherwise I don't see the point...well, I think the point of sex tapes are for the attention, and I wouldn't "get my feet wet" as most do, I'd dive right in and make it legendary.
And I wouldn't make one for any other reason. My rule of thumb is if anything about me scandalizing involving sex or nudity gets online (let alone a sex tape), it WILL reach eyes never intended, and that's guaranteed many times over for celebrities. As I'm not an idiot (at least in this way) there's no way I'd allow a sex tape to be made unless I wanted it to get out. If someone made one such tape about me without my knowledge then I'd use my wealth to ruin the said person, and perhaps others involved, and it wouldn't necessarily be by legal means, though private investigators to follow them around seems like a good start.
(Wait...decided to look up the particulars of KK sex tape, very careful what I click on but figure HuffPo is safe...didn't say, only that KK didn't want it to go and "initially sued" which I don't think proves anything. I'm gonna assume it's the usual fare, and KK does strike me as one who loves attention, but whatever, I don't really care.)
2. Never. Besides, they're scripted anyway.
3. Can't imagine why I'd pose nude, but I wouldn't care if candid pix were taken of me on say a nudist beach where everyone else is nude (or allowed to be).