well i wasn't mentioned but a question can get taken down if ur mention isn't of good intention. iv seen users mention on their questions and they were all ok cuz the question was in good fun =]
i had a girl take my picture and use it to ask her own question. 'rate her, what do u think of her?' she also blocked me so i couldn't say anything but thankfully some of my user mates who recognise me sorted it out so i thank them for that, as i have done a few times telling this lol.
I think it can be taken down if you contact GaG admins. Apparently a member mentioned me in his question, saying I'm amazing but it got taken down so quickly that I didn't even have a chance to see it myself. I thought mentioning users was forbidden though, and that the question you mentioned would be removed as soon as they noticed it.