It is extremely easy to setup extra email accounts, so preventing people from doing so with slightly less work is pointless.
It is stupid because it could prevent someone from using their real, valid email address because it matches another, different, valid email address.
It is extremely easy to setup extra email accounts, so preventing people from doing so with slightly less work is pointless.
It is stupid because it could prevent someone from using their real, valid email address because it matches another, different, valid email address.