Waistbands should keep your (sweat)pants up

Waistbands should keep your (sweat)pants up

A while ago I bought 4 pairs of sweatpants for my daughter. Even though they were bought in the same shop at the same time and 3 were the same model, 2 fit just fine and the other 2 simply slid down her legs and ended up at her ankles when she was wearing them. Not...