A FAQ is nice but there is no policing to enforce it.
The only way to enforce is by reporting people to
their ISP. The ISPs don't act unless it's an obvious
and continuous problem. But even then, the person
can so easily get a different email or news-service
and be right back here.

This should be researched I guess.

My understanding is that ISPs take abuse seriously, they can't really afford
not to and it's easy enough for them to do. The research would be provided
by the charter holder and simply double-checked by the ISP staff. The ISP
deals in volume so cutting off one customer is too small a number to have an
impact on revenue. The poster would then have to get an entirely new account
with a different ISP. I would think this would be good motivation for not
screwing around.

In fact I would be inclined to think that it would be resolved in the formal
warning phase.