That is 100% false.
One thing to always keep in mind...
The "phone CM's" are not trained in, nor do they have any inside knowledge of,
WDW operations.
But, that does not stop them from making up answers, regardless of how wrong they may be.
Also know that the answers on these boards can be MUCH more accurate, even though
most of us don't work for Disney.
Why?
Because if any of us makes an error in our replies, it only takes a matter of minutes for
a half-dozen, or so, other posters to jump in and correct the blooper info.
(Don't ask me how I know this.)
That kind of nearly instant "peer review" makes these boards invaluable when
discussing the "rules of Disney."
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As to the info that a guest must buy a 2-day ticket to get Free Dining, THAT is true.
But, that is actually a 2-day MINIMUM ticket.
Guests can purchase a much "larger" ticket, up-front, if they choose.
(And, since advance FP+ requires a valid ticket for every day that FP+ is booked,
it would make more sense to purchase a ticket with enough "days" to cover your
upcoming trip.)
AND, once that ticket is PICKED UP and USED (at least one time) by a guest, that same ticket can be upgraded in any way the guest chooses...
with no effect on the Free Dining entitlements.