What I basically am wanting to know is if we are running late, how long is our ADR kept? We are always on time wherever we go, but could see losing track of time.
This happened to my family last year. Large party most of us were there while one part was running late. They said they would hold for about 20 min then after that they couldn't give us a guarantee. I totally understood this (it was 'Ohana). We were 30 min late and we did get in shortly after (thankgoodness for good shops).
I think officially it's something like 15 minutes, but it surely depends on circumstances and the CM at the podium.
Why not err on the side of being early rather than late? We are constantly showing up 30 minutes early for our reservations, because trying to do something else first would make us late. We are usually seated well before our actual reservation time.