It just guarantees you that you'll get seats/parking and gives you the opportunity to select in that section/lot if there are remaining seats/spots when it's your time to select.

I believe the order forms went to everyone who made a donation and/or had season tickets last year, so if you were a new HC member who made their first donation after 3/15 and looking to buy season tickets for the first time, I could see how you may have ended up in a black hole. That does add more rationale to have the ticket deadline be the same (or later) date as the giving deadline. I'm not sure why they set it earlier this year- I think with all the changes they just wanted to get an earlier handle on how many orders they were getting.

If you don't mind sharing- what was your HC ranking on 3/31? I can definitely understand your frustration about having multiple deadlines. Not sure if this will make you feel better, but if you are a new Silver Hokie, you'd literally be the last person "in line" at your giving level, so whatever inventory they have now for that level donation minimum is probably the same as what would've been available for you to pick if you were given a selection time.