Some players forget to check in for a tourney and are then bummed when it starts at they aren't in it. I like the check-in aspect, as it saves people points when they for some reason miss a tourney without unregistering, but perhaps some small improvements could be made.
Not lobbying for anything in particular, just gonna throw you some ideas:
1) A reminder flashes at various times on a players screen. Perhaps 10 min, 5 min, 2 min, and 1 min - for players who are not yet checked in.
2) If you register for the tournament within 5 or 10 minutes of it starting, you are automatically checked in, since obviously you are there and present shortly before the tournament is set to begin.
I think something along these lines would be good, especially for new players who may not realize the check-in process, even though to me its rather clear (but even veteran ice9 has a habit of forgetting the check-in phase