A lecturer came up saying he wants to notify all students simultaneously about graded assignments and he's tired of all the times having to uncheck the "Notify students" checkbox when he grades. And he does re-edit the single student's feedbacks and grades several times so that is a lot of unnecessary unchecking.
There is a way of circumventing this but that way isn't alluded to. Moreover, in certain cases (when using marking workflow and in "In marking" status) notifications are not even sent although "Notify students" is checked.

TO REPRODUCE:

1. As teacher, in a course, go to a assign activity in which almost a student has already turned a submission in.
2. Click on "View all submissions".
3. Select all and do "With selected..." → "Set marking workflow state" and press "Go". (Confirm the "Set marking workflow state for all selected submissions?" popup.)
4. Choose "Marking workflow state" → "In Marking" and press "Save changes".
5. Note that each submission has "In marking" under the status in the "Status" column table cell.
6. Now, press the "Grade" button on the submission to grade.
7. Note that "Notify students" is checked (provided that in administration assing|setstudentnotifications is set to standard yes and not overridden in the assign activity itself).

If the marking workflow state is set to "In marking", no notification will be sent out. Therefore an information would be appropriate to emphasize this.
Both use cases should be tackeled: informing graders whose notification were not sent despite they were expected to be sent and the other use case for graders who search to circumvent having to go to uncheck the checkbox each time since the want to notify all students simultaneously but are unaware of the grading workflow's possible ways.