Sepp Dietrich was a general in the Waffen SS, and one day when hopping out of a tank he slipped on the steel hull, fell, and seriously broke his arm. In 1967 I came into possession of a pair of Dietrich's jackboots. The iron hobnails had been replaced with rubber ones! Obviously the general had learned his lesson. A few years later I saw a pair of Lord Mountbatten's white Navy oxfords, complete with rubber cleats set into the leather soles to prevent slipping on the decks of HMs ships. Yes, for those of you who haven't experienced it, leather soles when wet can be as slippery as ice.

In 1974 I had a bit of a fall coming down some marble stairs that were damp after a bit of rain. The heels of my riding boots were held on (I guess) by a bunch of small nails, I lost traction, and ended up bouncing down a half dozen stairs on my rump. Needless to say, this was not the best day's riding I'd ever had!

My take on hob nails, and heel and toe plates, is that they aren't worth the risk.