My high school also had a Sadie Hawkins dance each year. I graduated in 1997. But it was more like any other dance, not a formal. I seem to remember couples dressing alike for it? (Which, in retrospect, is both cheesy and a bit creepy.) The Sadie Hawkins dance was also always held in fall, closer to Sadie Hawkins Day - never in spring, partnered with a “spring fling” dance like on VM.