It seems that some drivers still don't believe that they will be caught by average speed cameras. Despite years of operation, many still speed through these point-to-point zones.
Although only a small fraction of the overall amount of motorists who travel through these zones are caught, it still represents a significant amount of people that are either ignorant of how these cameras work (including foreign drivers), lose concentration or blatantly ignore the speed limit. Many probably believe that they aren't actually switched on.