Scenario: Foot leaves the last “two rungs” on upper section of extension ladder, with at least half of the foot being in contact with those two rungs…..but the next step down is now a single rung….the foot moves down expecting to land on two rungs….the angle of descent stays the same, so only the front toe section lands on that inverted single rung. UNLESS the foot moves forward to allow the same area of foot contact………you may say that the foot automatically does that…..well yes, if you know that the single inverted rung is about to arrive, maybe by glancing down? Maybe by remembering where it is? But if you are not expecting half of your foot landing to suddenly disappear, then however anti slip that rung is, the weight of downward movement at that point is transferred to the rear of the foot.
Result: THE POSSIBILITY OF A MAJOR SLIP AT HEIGHT.