I agree that no interview process is perfect, but Behavioural Based interviewing comes closer to helping us achieve our objectives than anything else right now.
Yes, candidates can bluff their way through any type of question, but in an interview situation, you are testing the candidate's ability to prove their worth to you. By making candidates talk about actual situations they have been in and how they handled them, you learn a lot more about the person. Most skilled interviewers can tell if the candidate is being less than honest. I know I can. When I come up against those sort of people, I just ask a few supplementary questions about the situation they have described and catch them out.
Perhaps you could tell me about a time when you asked a candidate this question. What was his reply? How did the information affect your hiring decision. What was the result in the end?