[Mithalwen]

There is also the simple fact that one is vulnerable to new or new-to-you strains of disease. Think of how the Europeans wiped out native populations in the colonies with their diseases as their weapons.

I took a gap year befor university and worked for six months in a pharmacy. All day long I was exposed to the sneezing and snuffling of the local sick collecting their 'scripts and buying cough lozenges. The only cold I caught that year was the one my sister considerately brought home from the other side of the country.

I agree however that if you scare someone enough the physical becomes irrelevant, and it is unlikely that Sauron had any humanitarian concern for his troops.