Require users to review some pre-selected records. To set this up, you need to go to:

The linked record on the form will display a red dot on its upper left side, indicating that the record has not been reviewed by the form user. Simply clicking on the record will open the child form and remove the indicator.

Enforcing opening linked records would only apply to existing (previously linked) records, not ones newly selected or created by the user. A use case example: to-do list where each task is a single linked record.