Oliver just asked for this, and we spec-ed out a rough idea of how to do this. Some thoughts here:

• New registrations now start out "unprocessed". "Processed" registrations get moved to the waiting list, which means "this registration looks legit, and I'd like for this person to compete at my competition if there is space for them"
• Registrations on the waiting list are automatically marked as "accepted" if there's room for them in the registration list. This includes handling the case where an accepted registration is deleted, thereby freeing up space in the registration list.
  • NOTE: Do we want to allow changing a registration from processed to not processed? I believe we should allow changing a registration to not processed, IFF that registration is not accepted.
    • NOTE: I'm undecided if this should be implemented with 2 booleans: processed? and accepted?, or if it should be a single enum with 3 states: unprocessed, processed AKA pending AKA on-waiting-list. I am kind of leaning towards the enum...
  • NOTE: What about moving a registant from the accepted list to the pending list? Do we want to support something like that? It's weird, because if you try to un-accept someone, space frees up in the registration list, and then you have to pick someone from the waiting list to accept, which will be the person in the waiting list who registered earliest, which is probably the very person you just tried to move off the registration list...
  • Notify people when their registration is automatically moved from the waiting (aka: processed) list to the accepted registration list.
    • Also notify everyone still on the waiting list that they've moved 1 spot closer to competing?
      • NOTE: This seems potentially spammy, especially if the organizer is deleting a couple of people from the registration list, as each deletion will cause a slew of emails. FURTHER NOTE: We're already hitting our Mandril email limits pretty quickly, we'd have to decide just how much money we want to spend on emailing. See this screenshot from February 9th (9 days into the month, and we're already at 8.1/12k free emails):