If you order a ticket online with an unlimited card you're supposed to pick it up no later than 20 mins before the showing starts. Otherwise they say they will release the ticket back on sale. They haven't been doing that though. I have got there 15 mins after the advertised start time and been able to pick my ticket up.
I'm sure last time I booked online with my Unlimited card it just said they advise to pick up 20min prior, but that they need to be picked up before 10min after the start time otherwise they will be cancelled.