About spam from banks where you have no account ...

Wait until the bank with whom you do no business sends you confidential data, and that bank has the court temporarily suspend your (Business? Church?) email account.

For that decision, U.S. District Court Judge James Ware has won Jackass of the Week from Daring Fireball and a variety of somewhat more explicit characterizations at Slashdot.

Wyoming-based Rocky Mountain Bank started it all by complying with a request to send loan documents to a customer, and complied by sending the too much data to the wrong address. Rather than merely send loan documents, the employee also sent "a file containing confidential information for 1,325 other customers."

Then, according to The Register:

After a failed attempt to recall the email, the employee sent a second note to that wrong address, requesting that the confidential email be deleted before it was opened. There was no response, so the bank contacted Google to determine what could be done to ensure that the confidential info remained confidential. According to the court papers, Google would not provide information on the account unless it received a subpoena or "other appropriate legal process."
So the bank sued.

A truly bizarre series of events, since only a digital security nitwit would do anything with email purporting to be from a bank with which he does not do business, other than delete it. Because such emails are typically both scams and vehicles for malware.

But you can protect yourself (Business? Church?) from this sort of thing, can you not? Without exposing yourself to both endless distraction and malware?