Your 'block' doesn't work
Block means block. It should get kicked back to the sender as an invalid e-mail address. The goal is to make my address unattractive to spammers. A bad e-mail address means they remove it from their system. Removing it from their system means they don't share it with other spammers.
If Block only reroutes it to the trash bin, this is nothing but a glorified spam filter. So quit deceiving your users and actually Block the trash we want blocked