Apparently this is new, but I suspect most people that have been in sales, or professional advice, for more than a couple of years will have already figured this out. People first need to trust you before they can respect you. That initial liking, of the kind where they know you sufficiently well to rely on you, precedes competence. When you think about it, its obvious really. If someone is super-competent, but untrustworthy, then they are more likely to do me harm than someone trustworthy but less competent. Nevertheless, this post is worth a read: link.
When people cannot work out why poor advice is tolerated it is often because they have overlooked the value the customer placed on their trust in the adviser. When some people look at sales processes and break them down into mechanical steps that, at first glance, it looks like anyone could perform, they are overlooking the necessity for trust.