Last year
MDE had my youngest daughter's ticket, profile, messed up. I didn't even bother trying to get it fixed. But I was experienced enough to know that I needed here physical ticket to get her in the parks, so I brought it. I was right, everyone's magic band worked just fine but hers. I used her ticket to get her in, use her fast passes and such. I was just glad that I had been enough times to see that there was a problem before hand. Make sure everything is right before you leave.