How many Optima OUSCI cars did not compete?

[GNon18s]

Are cars getting invited to Optima's USCI and then not participating in the actual competition? I was at SEMA and OUSCI this year as a spectator and it seemed like a lot of cars that had the Optima invite were not driving at the event. Also the results on Optima's website show a lot of 0's for the driving portion of the event. Granted, I didn't get to the track until @10am, but I got the feeling some people get an invite to this awesome event and then aren't participating.