Lock fields until governing "Enable" checkbox activated

For date/time picker fields that require an “enable” checkbox to be selected in order for the date/time to be used, the date/time picker should be unselectable until the checkbox is checked.

Example / Replication: 

1. Navigate and select to create new announcement
2. Enter title and body text
3. In Availability select Specify dates option
4. Beginning and Ending options appear with an enable checkbox to the left and date/time picker to right.
5. Without checking either enable checkbox, user is able to change date/time pickers to desired values.
6. On user’s attempt to post announcement, user will be redirected to same page and an Alert at top will indicate “You need to select a Beginning and/or Ending Date when specifying dates!”

Reasoning: A user needs to enable one of these checkboxes to be a valid release. With the date/time picker selectable at all times, it is not apparent to user that they also need to select the checkbox to activate the setting. In addition, if you forgot to enable one of the checkboxes and try to post, you are returned to the Add page with an Alert message appearing. When you go back to the Specify dates option, the dates/times you previously selected aren’t saved and you must re-select. As an end user, you have selected a date/time that are valid (e.g. in future) so the alert message is not addressing the real issue of enabling the date/time picker. 

Comparison: Providing an example of another LMS with similar interface

Sakai experience - https://youtu.be/CjGVU5PoNNE

Moodle experience - https://youtu.be/aqdEpyXDYHk