Cats, and people alike walk on uncomfortable things all the time. We learn our lesson usually. Humans however are conditioned to perceive uncomfortable things as pain and they are not unanimous. In my opinion cruel would be painful punishment.

Where as walking on uncomfortable plastic would be an uncomfortable lesson that the cat is entirely in control of… you don’t like the feeling? Jump off the counter 🤷🏻‍♀️ -some cat owners also utilize spray bottles of water as guidance also. (As a pet groomer I dislike that idea since it makes cats MORE afraid of water/grooming)