There would be absolutely no point in namechanging if your posts are still up there for some weirdo stalker to find, would there?
I agree. but I do NC nonetheless, but only ever to protect myself from being outed/stalked by people I know in RL. I can't stop it happening but I can make it harder work, by keeping on the move as it were.
I did once get very panicky and ask MNHQ to delete a bunch of posts that specifically referred to the country I had moved to (and they very kindly indulged me) because it made me pretty identifiable to anyone who knew me in the UK. Anyone motivated enough to spend a couple of hours AS-ing could piece together enough aspects of my life in the UK and match them up with my new posts about moving abroad, and the relevant timings etc, and see clearly that it was me. It would be a piece of piss.
At the time I was a new expat and I was on a few Expat message boards doing a bit of networking as you do, and my mother cheerfully announced that she'd been on a fact-finding mission about the place I'd moved to and she'd recognised me (even with an avatar) from those boards. To say I was spooked and appalled was an understatement, because she is very nosey and a master internet stalker of everyone she ever knew EVER because she's bored and has no life. I'd said nothing of interest/controversy on there at all but MN is another matter entirely....and I felt potentially quite creeped out and like a really important part of myself had been violated. Like she'd read my diary. Which is possibly an over-reaction on my part because I don't even know if MN is on her radar at all, but the thought of it made me feel a bit sick.
I have NCed reasonably regularly ever since, but I know that a few choice key words would make it easy for her (or anyone) to work out my other user names, and gather a trail, should they feel so inclined. But the onus is on me to be a little bit sensible and circumspect, isn't it?
Much though I'd sleep well at night knowing no-one could ever do another AS on me, I admit I love a good AS myself from time to time, so I just have to roll with it, like everyone else. At least I think like everyone else? And if I've ever been an utter arse, or contradicted myself and it's there to haunt me and give ammunition to others forever more then tough titty, I'd have thought. It has never occurred to me to ask for an entire history deletion though I wish for it often usually the morning after too much gin has been taken and I may have over-shared.
I'm fairly sure the answer would be 'No' anyway, unless I could prove some dire/urgent need like in the handful of previous very well documented cases. But they tend to come off the back of well documented exciting/terrible back stories that go around MN like wildfire so it's obviously a bit 
when it happens out of the blue for no reason you can think of.
I'd just like to know where the criteria/boundaries are set with MNHQ and that it is applied consistently and fairly and not just because someone's thrown their toys out of the pram. Or if they have then can I throw mine out too if I feel like it? 
But I realise that:
a) MNHQ can use their discretion however they see fit and do not have to explain themselves to me, or anyone, and
b) there may be a serious security/privacy issue I am unaware of.
But I don't expect or even want them to comment on specific cases.
So is that it then MNHQ? TSSDNCOP? Nothing to add?
And to all the people who have PMed asking for some juicy detail, forgive me if I don't answer any of you personally. There is no great drama or gossip to divulge - at least if there is then I am certainly not party to it, so no point in asking me.
I just wanted to know where we all stood on our histories, for the reasons outlined above.