Why associate any account you use with an email address you don't check.

Point taken. Yes that could be a possibility, but with something in the system, it takes up 0 time from any admins/mods so the "mailman" is incorrect. Also so what if you get the messages and you don't check it? Who does it harm? Right now if someone has a non-active account and email, then nothing happens. This would still be the same, But if they had an active email but not account they would be like,

Oh thats my friend waiting for my relpy!" So they would BECOME more active.
I know you will probably say, well what if people don't want the emails, then give them a "no notification" setting!