Yup.
But, I just want to state that the ubiquitous announcement of
the "15 minute grace period" is not an actual WDW policy or rule.
It is really a much-repeated Disney myth.
It just gets stated and restated so many times that it has "become a rule" in cyberspace.
WDW is SO enormous, and confusing, with so many (sometimes unavoidable) pitfalls and delays, that
a massive number of ADR arrival times are missed every day.
I like to put it as "
Everybody is late at Disney" at least once (if not more,) per trip.
(Consider the infamous monorail delays, bus arrival snafus, slowdowns in security checks (as it is unpredictable how "slow" the bag check lines will be
at any given time,) and hapless guests being locked in non-moving ride vehicles for various reasons beyond their control.
With the countless thousands of guests having ADRs booked daily at venues at the parks, resorts, Disney Springs and Boardwalk,
if Disney "only allowed" a (tiny) "15 minute grace period" for all of those, they would be turning away hundreds of paying guests every day.
("Your party of 8 is 19 minutes late... Sorry, you're out!")
OTOH, if guests are lucky enough to NOT be delayed by whatever sundry difficulties lurk, that's great (and most do arrive "on time/ or (the suggested) 15 min. EARLY."
But, if you do get slowed by the X-factor that is the checkerboard of unseen pitfalls that are part of the fabric of WDW,
go on to your ADR and nicely ask if the restaurant can still fit you in...
After all, "
Everybody is late at Disney."