It would be like putting little smiley faces on Auron's sword.

"Rikku! Put that paint down right this instant!"

"You never let me have any fun!"

"I'm only doing this for your own good, you know. And by 'for your own good' I mean 'because I really don't want you to die horribly until you finish teaching Tidus how to steal things'."

"Gee, thanks."

"Where'd you get half a gallon of red paint, anyway? Do I want to know?"

"I picked it up in Guadosalam. No one seemed to be using it."