As a cloth diaper wearer, I often have trouble with the smaller 2" pins opening up, but not with these pins.
I also bought two black onesies to go along with my yoga pants. Before I got these, my tank-top used to ride up and expose the top of my plastic pants, even my lowriders. I now wear a thin daytime diaper and plastic pants under my onesies to be a little more discrete about my wearing them. They work great.