In Yahoo! Mail, in the settings section, we have an item named "banned addresses", which means that we normally don't receive email messages from that address. It doesn't go to spam, trash, etc. We just don't receive it.
But in Gmail, blocking an address means sending messages to the spam folder.
And if you create a filter for that address and choose the item
delete it, it just goes to the trash folder.
So you have the chance to open spam and trash folders and see the message. Is there a way like banning a certain address in Gmail?