Hopefully I'm the only one who has experienced this, and others' experiences can prove this wrong:
When we went to MVMCP (as paid ticket holders), there were several people wandering around without the wrist bracelets on. At first I just figured they forgot to get their bracelets. Then, as we were waiting for the parade, a young couple sat down next to us. I noticed they didn't have bracelets - my curiosity got the better of me, so I asked them if we actually needed them (it was my first MVMCP, so I wasn't 100% sure). They giggled and explained that they have it all figured out...they never buy tickets and go every year. Apparently, they make ADR's for an MK restaurant and stay in there during the park clearing process. Then they head out to the parks and join the party. I couldn't really argue with their process because to be honest, we had ADR's at CP that night and got out around 6:15pm...we wandered over to Adventureland and hung out there for quite some time before getting our bracelets. Many CM's walked right past us and didn't challenge us.
I'm not saying that this is how it always goes, I'm just relaying my experience with these two dishonest people. I found it sickening that they bragged about beating the system, but to be honest, Disney wasn't doing a good job keeping it a ticket holder only event IMHO. And the event was MOBBED. I couldn't possibly count all the people obviously, but it seemed far more crowded than what they advertise the maximum ticketholders to be...so I'm guessing this couple wasn't the only group of people doing this. Such a shame.