New Fashion Trend?

My son has decided that wearing his short sleeve shirt on top of his long sleeve shirt is "the thing" to do. Apparently one of his friends at school showed up that way once and it has been what my son has tried to do since. Today he wanted to take it to the next level. It's cold outside and I've taught my kids to layer for warmth. So he wanted to wear *2* short sleeve shirts on top of his long sleeve shirt. I got a compromise out of him. One under his long sleeve, one on top of it. 7 year olds, go figure.