Why are PJs so tight?

Have you ever wondered why the fire retardant PJs are SOOOOO tight? I know loose clothing catches on fire more easily, but you need a crow bar just to get the kids in and out of the PJs. We have one set of long sleeved "super tight" PJs and they are a size bigger than the kids actually wear but I really think you need 2 or 3 sizes bigger, which of course defeats the whole purpose of the PJs I guess. Anyway, just thought I'd throw that question out there. The kids do look cute in their PJs; I'll post some pictures in the morning of them. Abby's has a cute strawberry on it and Jake has a fire truck.