Is an email still spam when it says they stopped (past tense) sending you e-mails?

Yahoo injects marketing messages in footer of emails sent by users of its service. These can trigger spam filters, so recipients don't get them, and should, but probably doesn't, violate anti-spam legislation.

Complaints about tiering internet traffic are well meant, but misguided. Tiered models for traffic throttling abound in the real world, and the real world loves them. Why not the net? Don't we want content we've purchased to arrive faster than spam?

Trainable spam filters do a pretty good job of catching phishing attempts, but do highly public infrequent correspondents (that is, banks, Paypal, EBay, etc) need to be concerned that their legitimate emails will start to be caught in the same net?