How often do you see identical mailboxes (email address content before @)?

Question

Computer networks

Hello!
On our site, registration is carried out via e-mail, but in the database users are identified by login. Our login is the part of the e-mail before @, i.e. if a person has e-mail qwerty @abc .ru, then his login will be qwerty.
Logins must be unique. Is it even possible to stumble upon a situation where people will have the same logins, i.e. that people with mailboxes qwerty @abc.ru and [email protected] will register? Or are these just minor cases that you can not be afraid of?
Sincerely,
Alexander.

Answer 1

A terrible decision, since the address is definitely unique in its entirety, that is, both the name and the place. Moreover, Vasya's namesakes, who studied with you at school, do not bother you? But even if it so happened that the fathers were also called and, suddenly, they belong to the same ancient family (read - namesakes), then what will be different is the series-number in the passport. So the identification must be unambiguous. Otherwise, collisions. You don't want a break in the space-time continuum, do you? So that. Do it wisely, or use a separate login, or the entire email address instead of it.

Answer 2

alexander @lashchevsky .me, are you serious?