If you are the sort of person who views garnishes with suspicion — that they are being used to hide some deprecation of the food they are meant to enhance, say — then you might be on to something.
The word garnish comes to us from the Proto-Germanic term warnejan, which lead to the Old High German warnon, “to take heed” and from which we have the English warning. The stem of the proto-Germanic word lead to the Old French garniss, or garnir in the 14th century, meaning “to provide, furnish, fortify or reinforce.”
To garnish, or embellish a dish in the culinary sense dates from 1700, and comes to us English via the sense of outfitting oneself with arms for war.
If you have a lot of time on your hands, you might want to explore some extreme garnishing by turning two innocent apples into turkeys. Be sure to use plenty of lemon juice so they don’t turn brown halfway through!
Garnishing: A Feast For Your Eyes, Francis Talyn Lynch, 1987