[somethingAlex]

The consistency level seems to be Causal Consistency, which does include read-your-writes. S3 doesn't provide ACID transactions, so stricter consistency models aren't really needed.

From what I've read, if a network issue occurs which would impair consistency, S3 sacrifices availability. The write would just fail.

But this isn't your 5-node distributed system. Like they mention in the article, the witness system can remove and add nodes very quickly and it's highly redundant. A network issue that would actually cause split-brain or make it difficult to reach consensus would be few and far between.