The answer is no
Will they still scan when CB band is full of skip?
Channel scanning is one of those features that really make no sense on CB. You will learn very quickly that there are at best two or three channels in your area that are active with locals, and you will settle on one of them for chatting. CB channels have so many carriers, odd signals, and noises, that most scanning functions stop on those channels. Skip is a good example. If skip is rolling in, your scanner will stop on these channels and will quickly become useless. A scanning function simply stops on every signal - it cannot tell the difference between a local signal and a skip signal.
Most people use CB either to use the trucker channel on the road, or some other pre-arranged channel with some people, like truckers entering a warehouse area or a gravel pit, or some other pre-arranged channel with a friend going hunting. I have never known anyone who thinks that a scanning function on a CB radio is worth anything, and I have been in CB since 1973.