Most of the racers on the ice had studs, most are riding stock studded tires. Lake ice can be challenging, and it was 0F on this day, so the ice was very hard. Everybody was messing with tire pressure to find something that would give you the most grip and get the max number of studs in contact with the ice at a time. I found it basically came down to, don't make any sudden movements, no hard braking, no hard accelerations.
I'm not sure if the Facebook link will work, but I have a coupe buddies that were out with a group ride on Lake Minnetonka yesterday, the whole lake is a skating rink, smooth ice and no snow.
edit, I can't post this as a link in BF, so if you're a FB user, try pasting this link into your browser
edit the edit, screw it, that doesn't even work. Is there a policy against FB on BF?