Little girls with bright painted nails.

Is that a new trend, I've seen so many of my kids (student) come to school with brightly painted nails and different color nails. Mind you my kids are 4-5. When I was younger it was a no no. I know times have changed but I really don't like it, call me old fashion but what's wrong with clear polish of a light pink or brown if color is necessary? It's all a little too "grown" for me.