I understand your frustrations but an outright ban straight away isn't always the answer,
You shuld bear in mind that on certain forums it is perfectly acceptable to post advertising links.
Others it is frowned upon, others it is disallowed.
There are some forums where you could be warned/banned for suggesting how the administrators should do their job better outside of the right section
Everybody needs gentle guidance and time to re-adjust when they enter a new forum, imediatly banning people, when they genuinly don't know any better is not the answer.
and those that are determined to spam will spam anyway regardless of post count limits set on a section.