Don't own that color. Navy is a popular college football color, USU doesn't have a monopoly on it.
The USU theory that BYU stole the color from them is stupid, which isn't surprising since it's from USU fans. Penn State, Yale, Navy, and Notre Dame are all older programs than USU and all wear navy. Did USU steal their navy from them? USU didn't create the color navy and wasn't the first to use it so their claim of stealing is dumb.