Daguello was in fact the Mexican army’s signal that no mercy would be shown.
If I were a Mexican soldier & heard that played, I would be thinking “Caramba! We have just told the enemy they have nothing to lose by fighting to the last man. Like that’s going to make our job any easier! Muchas gracias para nada, senor general!!”
Heh Heh, I think playing “I’m Bad...I’m Nationwide” would have the same effect.