[Shamanmuni]

CAP is about choosing which are the main guarantees of a system. When you say P in CAP it means "If there's a network partition which affects n machines, the rest of the system will take charge of that load and continue working just fine" for a variable number of n. Saying "they chose CA" means they don't provide that guarantee and there could be problems related to a network partition (which by the way is how SQL databases usually operate). In RethinkDB's case they chose to sacrifice availability by default in those cases (but you can tune it).

Take for example Riak, they chose "AP" which means the system will continue working just fine through a network partition at the expense of not giving a strong consistency guarantee (eventual consistency). That doesn't mean that the data isn't consistent at all, just that it isn't its main concern.