Oh, we high school girls had our methods of circumventing the rules. If made to kneel (this sounds SO archaic now), we’d pull in our (mostly nonexistent) tummies and push our skirt down as far as we possibly could to pass the step test. The alternative was to wear a longer skirt to school and roll up the waistband as much as we dared. If questioned, all we had to do was unroll and kneel – test passed.
Getting back to the bell-bottomed pants – we weren’t allowed to wear those to school at all. Even to basketball games after school, it was skirts and dresses only.