Ushers and gatekeepers are under a lot of pressure to let everyone in--even those who shouldn't be admitted. We're always looking for ways to help them confidently and effectively greet your audience on the day of the show--because it matters big time.
But, yes, sometimes they need the nerve to turn people away. To help them enforce the rules, we've added clarity when rejecting a ticket at the door, letting ushers know exactly when any tickets have been previously scanned. This works on every device on both of our gatekeeping apps, Entry and Elevent at the Door (on iOS).
There's nothing you need to do to enable it--it's happening already.