Ticks in messages are allowed -

Is it an option to add an option that does advanced mail address checking? sample functions exist that level 1 check MX record, level 2 check for existance of the remote mail name. Level 0 can be no check - current functionality.

Addin this would be very simple, also we can set the option defaulting to level 0

link: http://www.devshed.com/c/a/PHP/Email-Address-Verification-with-PHP/

I think we can make some easy improvements here ....