Often consulting clients only want the consultant to validate what they've already decided to do. Sure, it's best if they listen to you; you are the "expert" after all. But sometimes the best you can do is sit back and do damage control after the fact.
Oh yes, some will want a certain type of advice but they still want the consultant to tell them that. But it seems to me that the idea here is that if the best you can do is wait for a chance to do damage control then you should try somewhere else.
It seems like you could hire someone to tell you you're right for much less than the cost of a consultant, though, since they wouldn't actually need to be any sort of domain expert.
