I can't speak for the Indy, but I did a couple of Navigators recently. On both of those they dropped the ticket idea & you went in just like any of the other shows. Providing you were there 10-15 minutes early there were plenty of available seats. By the start of show they were at capacity with standing room only. Which ever system they adopt, it's worth the effort. Enjoy it. Regards.
The tickets go on sale 9:00am at a desk on the promenade, if you go just before 9 you will get a ticket no problem. Same system for the second show the following week.There are 4 different days/times to pick from each week. If you want the best seats to view the ice show i would go 20- 30 mins before it begins. If you go 5mins before show starts you may end up behind a pillar.
Just to save any confusion, they don't go on Sale, they're free!