"Yellow" is the branch color of Armor troops [and back when, the Cavalry]. You might want to re-think your overbroad view of "yellow".
Cpt., Armor
MACV, Class of '71
Apologies if I have offended. Yellow does have that other connotation, and the song about the ribbons is a convict coming home after he's done his time - themes hardly befitting the brave soldier.