Drawings of Peek-a-Boo Hair - What Color is Hiding Underneath?

Peek-a-boo hair is a recent style trend that involves dying the inner layer of your hair a different color from the outer one. 

In these illustrations, the vibrant colors from the characters' hairstyles make us assume they have a playful side, a part of them we might not have caught at a first glance.

Do you think the characters featured are dying their hair just for fashion, or is there a deeper meaning to it?