I disagree with most people in the US are not going to be much bothered about them . The first two negatives cancel each other out--that is, that's what I'd mean if I had said this phrase.
"I would not be surprised if we don't" = I somewhat expect that we will have interruptions on a scale that is not acceptable to most Americans". The third negative is unrelated to these first two. So, the guy's saying 'I somewhat expect that we will have interruptions that are big/bad enough that a lot of Americans will be upset about them'.

And, sorry, caram., but I also think in your post, that scale is the actual subject, and should therefore take a singular verb. (I hate to disagree with a fairly new member; but on the other hand, I didn't want to imply that the post wasn't worth commenting about.)