If it was an old-style red ticket with many parts I can just about understand this, but I really don't see how an agent could take the wrong coupon off a printed ATB ticket. I mean, isn't it always the top coupon that they take? The only possible error I could see would be accidentally lifting the first two coupons if they were stuck together. But how can you accidentally lift the second coupon while leaving the first one in place? (Assuming that the coupons are stapled together of course.)