Does reindex honour _routing option

We have ingested a few parent docs and few child docs per parent. For all child docs we used _routing=parentID. So that child also sits on the same shard where the parent lies.

Now we had only 1 shard and called reindex to destination index with 2 shards.

Does the reindex makes sure that all child are placed in the same shard as the parent?

Based off of Reindex API | Elasticsearch Guide [8.2] | Elastic, yes it does.