Briguy I can't speak for Carnival as a whole but I was on the Glory 01-10 to 01-17 sailing and there was self assist debarkation.
I too wish they would do away with it. It started out to be something for people who did and would travel light but unfortunately has evolved into people trying to carry everything but the kitchen sink both on and off the ship. Getting on, there was one guy who had a huge suitcase that was so large that he had been told outside by a Carnival worker he would have to check it. He managed somehow to sneak it past her and actually get in the security line and --you guessed it--got up to the scanner--was told it was too large and he would have to check it but he insisted it would fit--naturally he created a problem trying to wrestle it around this way and that--finally had to go back out with it after holding up the line for 10 minutes. I hope he got a double hernia for his trouble.
Platinum guests are supposed to have priority debarkation and were told to meet port side in the main lobby at 7:15 a.m, which most did . However we were accompanied by numerous others who were not platinum, various others laden with their worldly belongings, etc. and pretty soon it was a just a crowd trying to get off. We were close to the door so were able to get away from the mob and were in the car and driving away pretty quickly. The same exact thing happened the last time I was on the Glory last Jan.
I'm sure with some better planning Carnival could come up with a system to allow people to stay in their cabins a little longer and to monitor the colors called so the debarkation can go a little more smoothly.
There's a lot of folks that think they just have to be first off, regardless of how late their flight is or how close they live to the port.