Edit: timtyler is one advocate of the "come on, AI developers know what they're doing!" view.
I wouldn't say that - and I don't think I was saying anything like that in the referenced comments.
I do think that humans accidentally dropping the reins is pretty unlikely - though not so unlikely that we don't need to concern ourselves with the possibility.
Of course, even without accidents, there is plenty for us to be concerned about.
Here is another example of an outsider perspective on risks from AI. I think such examples can serve as a way to fathom the inferential distance between the SIAI and its target audience as to consequently fine tune their material and general approach.
via sentientdevelopments.com
This shows again that people are generally aware of potential risks but either do not take them seriously or don't see why risks from AI are the rule rather than an exception. So rather than making people aware that there are risks you have to tell them what are the risks.