MBs, and APs.... (or anything else that looks like a Reservation, and MBs).....
Folks are often confused, thinking your "whatever" reservation is "on" your MB. It is not. It resides in one of several Disney (likely 1970's Mainframe) computers.
All ANY MB is, is a KEY into that backend system. ANY MB, AP Card, Shrunken Head from Jungle Cruise (waiting for that one) that has your identity key, will be able to PULL your data. It does not CONTAIN your data. Think of your House Key - it OPENS your door.... but if it is destroyed? Your HOME is still there
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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Now - common stuff that FAILS with these keys. Being "Keys", if the backend computer systems croak? BAD things happen. Pretend you have a KEY - but the LOCK is broken
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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This is why I advise everyone to get ANY Reservation Number by EMAIL. COPY it, put it on your CELL PHONE, and CARRY it. When (not IF), the WDW Computer System rolls over and dies, yet AGAIN? YOU will have a solid, documented RESERVATION NUMBER. One you can PRESENT. AP, DVC, 12 years, 2X per year.... RARELY, we have had to do this. But we HAVE needed to do this.
All personal opinion - I'm not necessarily right, no one else is necessarily wrong.