Scenario: your journal requires 3 reviewers. You send more invites than are needed b/c you know not everyone will accept the invite. However, in this case, all 5 who are invited accept the invite.
After the first 3 reviews have been received, there is the option to trigger an email to the secured, but now non-needed, reviewers on a paper, telling them their review is no longer needed. So reviewrs 4 and 5 would get that email in this scenario.
The problem with choosing to set it to trigger an email after 3 are received is that sometimes the now-unneeded reviewers are already well into reviewing the paper and are now told that essentially we wasted their time b/c we don't need it anymore. I'd propose the timing of the email be switched so that after the required number of reviewers ACCEPT the invitation to review, anyone else who tries to accept after that gets a "thank you but not needed" email.
