@Gilles The question in rev 1 is not "FAQ-compliant". It very much appeared to be looking for an attack technique from an arbitrary, and potentially malicious, offensive standpoint. Perhaps that's just due to poor wording on the OP's part, and that's why it was eventually edited and re-opened.
@Gilles Without the new context, it could very well be perceived as being intended to help facilitate a bypass of a hotel or other hotspot's registration portal to gain free or otherwise unauthorized network access.
As @ThomasPornin said, the color of the hat is primarily determined by the intents of its wearer.
@Gilles No way except for inference from how they present their inquiry, unfortunately. Again, this is why the question was eventually edited and re-opened.
@Gilles I have upvoted your meta post - laid out like that I definitely approve. I need to go and check to see the questions we closed for being black hat - from memory they did always seem to be around intent, or general crapness (ie I want to hack into someone's account - how can I do it"
@Gilles In short, if the vulnerability can't be found in the NVD, Secunia, etc., any discussion regarding its details or methods of exploit doesn't belong here.
@Gilles That's very different from discussion about an actual 0-day.
@Iszi Almost any practical security question can be perceived as "how can I break this?" or as "how could someone else break into my system?"
@Iszi "The question has no use for a white-hat." I disagree. In fact, I don't think there is anything that a "white hat" should ignore. He doesn't have to know everything, but nothing should be forbidden.
Consider this question: how do I protect my Web app against SQL injection?
I could very well be a blackhat question.
Given the answer: the best approach is to use (...) a blackhat might read that as: any site that does not use this approach might be vulnerable, I will try to break these.
Given the answer: filtering " does not work, a blackhat might think: let's attack websites which just filter "
