https://www.mongodb.com/docs/mongoid/master/reference/associations/#touching says:

> Any belongs_to association can take an optional :touch option which will cause the parent document be touched whenever the child document is touched:

"touched" is subsequently defined as calling `band.touch`.

Per our investigation it appears that the parent is touched whenever the child is saved (i.e. modified in any way, not necessarily touched), such that the correct wording would be:

> Any belongs_to association can take an optional :touch option which will cause the parent document be touched whenever the child document is updated:

As part of this ticket we should also verify there is test coverage for a non-touch update followed by timestamp check on the parent.