If I'm that kids parents, I'm like "okay you can absolutely paint your face, but maybe let's do school bus yellow on one side and firetruck red on the other?
FTR I'm kind of an expert on the topic. As a youngster I loved the crap out of painting my face for ksucatsu games. Half purple half white, duh. One time I had this brilliant idea to do a "K" on one cheek, a "U" on the other cheek, and then the pièce de résistance the "S" bisected my face. Like went across the forehead, looped down and back across at mustache level, and then finally looped back across the chin.
In terms of design it was immaculate. Unfortunately, people (mouthbrathing idiots) struggled to recognize the "S" (probably bc the color of the S changed when crossing facial hemispheres) so they were very confused about why I had KU painted on my face and why it was in purple and white. Humiliating.