Also, per the article, a single node system WITHOUT REPLICATION. That would hopefully be quite rare, as it means you have a single point of failure, with no automated recovery plan.

But as soon as you have replication...you have distribution, and what happens when a partition occurs, where the master can no longer talk to the replica(s)? That's where CAP applies; the system -will- make a decision about what to do, and in doing so will trade availability for consistency, or consistency for availability, for any given read/write scenario.