Who should be excluded from reviewing My question may be a duplicate of: Sound reasons for excluding a reviewer, but it is motivated by What do you do when you are asked to perform an official review for a journal of a manuscript written by your supervisor?. Because there is an obvious conflict of interest between a supervisor and supervisee this answer claims the manuscript never should have been sent to the current student. The issue I see is how is the editor supposed to know if the potential reviewer has a conflict if they are not listed as a reviewer to exclude.

I essentially never list anyone in the excluded reviewer box. I would likely alert the editor if I was asked to review a manuscript from current and past collaborators, supervisors and advisees as well as colleagues in my current and past departments. This becomes a long list of people to include in the excluded reviewer box and it is not clear to me that it is helpful to the editor. Are there standard people that go in the excluded reviewer box?
You don't have to do the job of the editor and list every possible collaborator with whom you'd have a conflict of interest. If these people are asked to do the review, they should be the one to warn the editor. You can list people that you think wouldn't be obvious, but again you are under no obligation to do this.

As the first question you link to alludes, excluding reviewers is mostly because you think they'd be unfairly biased against your work.