Bug with adding person with duplicate emails

[Tsenrae]

Steps to reproduce:

1. add n/John p/87438807 e/alexyeoh@example.com a/Blk 30 Geylang Street 29
2. add n/Doe p/87438807 e/alexyeoh@example.com a/Blk 30 Geylang Street 29

Expected: Error message as duplicate emails should not be allowed

Actual: Command is accepted and duplicate emails are shown in the UI.

[nus-pe-script]

Team's Response

No details provided by team.

The 'Original' Bug

[The team marked this bug as a duplicate of the following bug]

Contacts allow duplicate emails

While two people in contacts can not have identical names, different people are allowed to have same email addresses. This is not likely to happen, and it is better to be captured.

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_{[original: nus-cs2103-AY2324S2/pe-interim#5569] [original labels: severity.Medium type.FeatureFlaw]}

Their Response to the 'Original' Bug

[This is the team's response to the above 'original' bug]

In reality, there are people who share the same company email.

We wanted to accommodate for this case, and impose fewer restrictions on the user.

Items for the Tester to Verify

:question: Issue duplicate status

Team chose to mark this issue as a duplicate of another issue (as explained in the Team's response above)

• [ ] I disagree

Reason for disagreement: [replace this with your explanation]

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## :question: Issue response Team chose [`response.Rejected`] - [x] I disagree **Reason for disagreement:** Though you do say that there are people who share the same company email and wanted to accommodate for this case, this is not stated in the UG at all. You cannot expect the user to know this as an average user would be confused when they see that two of their contacts are able to share the same email, when in the real world, personal emails should be unique to each user. Furthermore, based on this screenshot below taken from the 2103T website, for bugs related to duplicate detection, it is not trivial, and that your team is expected to make the limitations clear to the user so that users are not led to believe that duplicates are being detected while many potential duplicate cases go undetected, and that this bug can be considered under a type.FeatureFlaw. This is an exact case of this bug report, as you could have either made it clear in the UG why duplicate emails are allowed, or provided a warning to the user when they tried to enter a duplicate email.  Additionally, since your target profile is small restaurant family owners, I believe it is reasonable to not allow duplicate emails as this is a field that can potentially be used for verification purposes (eg. making sure that the customer is actually the person that made a reservation), and thus a duplicate email may result in complications in such a case.

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## :question: Issue type Team chose [`type.FunctionalityBug`] Originally [`type.FeatureFlaw`] - [x] I disagree **Reason for disagreement:** To reiterate, this bug report is an exact case of this case shown in the screenshot below, taken from the 2103T website. Hence, this bug should be considered a type.FeatureFlaw, and not a type.FunctionalityBug. 

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