Thats interesting. We had an issue with my DS using my ticket but it did NOt go thru, we tried again, no go, then Cm walks over, looked at all 3 tickets and was straightened out though I cannot recall HOW.
I think the scanners actually DO work, who knows, I'm one of those that would be MORTIFIED to try and use some one elses (partially used?) ticket, etc. I always think about those people on ebay that get "stuck" with a ticket that were NOT able to use, sad!