Most bullets fired in wartime, or mines (sea or land) laid never strike a target. They can have a profound effect on behaviour.

Interestingly, that notion is one of the two uses of the word "invisible" in Adam Smith's Wealth of Nations. It's the very abitrarieness and randomness of consequences which is the primary mechanism of effectiveness:

Regularity, order, and prompt obedience to command are qualities which, in modern armies, are of more importance towards determining the fate of battles than the dexterity and skill of the soldiers in the use of their arms. But the noise of firearms, the smoke, and the invisible death to which every man feels himself every moment exposed as soon as he comes within cannon-shot, and frequently a long time before the battle can be well said to be engaged, must render it very difficult to maintain any considerable degree of this regularity, order, and prompt obedience, even in the beginning of a modern battle. In an ancient battle there was no noise but what arose from the human voice; there was no smoke, there was no invisible cause of wounds or death. Every man, till some mortal weapon actually did approach him, saw clearly that no such weapon was near him. In these circumstances, and among troops who had some confidence in their own skill and dexterity in the use of their arms, it must have been a good deal less difficult to preserve some degree regularity and order, not only in the beginning, but through the whole progress of an ancient battle, and till one of the two armies was fairly defeated. But the habits of regularity, order, and prompt obedience to command can be acquired only by troops which are exercised in great bodies.

https://en.m.wikisource.org/wiki/The_Wealth_of_Nations/Book_...

(Actually, "invisible" is used twice in that passage, vs. once in the better-known, and grossly misrepresented, passage.)