I experienced this one to the extreme. Not only would the recruiter not tell me what the scope of the job was, neither would the interviewing engineers nor the hiring manager. I went to the on-site interview with the promise that I would be working on "world-changing technology". The location of the interview was a nondescript building in the Bay area with an off-limits engineering pen I wasn't allowed to see. They kept me in a 10x10 cubicle with a white board and small table for 6+ hours during which a parade of engineers came through to ask me puzzle questions. None of the interviewers could answer simple questions like "What do you do?" or "What am I going to do?"
Seriously, how does anyone accept a job without knowing what the job is? I guess if you're a big enough corporation you can get away with that kind of thing.