So when the NSA intercepts your hardware before it's delivered?
Just look for the guy in the black suit, sunglasses, and earpiece lurking around the door of your server room with a cell phone plugged into his laptop.
For example, there's nothing on wikipedia's email page or "online service provider law" pages about this, so, no, I'm still not convinced it would be a huge deal to tell people that you're dumping spam, and then dump spam.
That would be fine. Again, it's the 'accept, then silently delete' that's the problem.
And in this case, it should be marked as spam, and either a) held by the ISP for some period of time, per the ToS that the user agreed to, or b) delivered to the user, marked as spam, for them to do with as they see fit.
The ONLY situation that anybody here has described that MUST NOT HAPPEN is this chain of three steps:
1) Recipient's ISP SMTP server accepts a message
2) Recipient's ISP SMTP server decides the message is spam
3) Recipient's ISP SMTP server deletes the message with no notification to anybody
There have, in fact, been lawsuits over this sort of thing.
The ISP must either a) refuse the message at time of delivery, via SMTP reject code, or b) accept the message, and hold it for the recipient. If the recipient chooses not to then access the message, that's their lookout.
The UK's Society of Motor Manufacturers and Traders has responded by saying that car companies "invest billions of pounds to keep vehicles secure as possible"