Skipping prom for a prerelease would be way worse than skipping for a regional though. At least with regionals there's big prizes on the line, so it's somewhat understandable. If anyone skipped prom for a prerelease or even a city championships or states even, well, then they may need to straighten out their priorities, lol.
I didn't go to prom cuz I didn't have the money to spend on renting a tux and all that and a date and what not. From what I heard, I didn't miss much. I guess a lot of people thought it stunk. lol