RBLs generally aren't used to outright block mail. A responsible mail host will assign a score (using something like SpamAssassin) to different traits. Presence on a particular blacklist is worth a certain number of points on that score. Other things like what's in the subject line, whether the server connecting to your server is following the RFCs strictly, the Bayesian analysis of the message vs. spam received in the past, and stuff like that feeds into the score.
This will mostly make messages from your domain or about your domain score higher in these spam filter.
The decision to actually kick a domain off of hosting is a final and drastic step taken by actual people. It will involve the hosting company notifying the domain's owner a number of times about the spamvertising if the spam isn't coming directly from them. The hosting company will check the WHOIS for where the spam is coming from to see if it's something obvious like the same company or the same physical postal address as the site being advertised. They'll contact the admin of the IP range sending the spam and get the IP range added to IP RBLs along the way, too, so just spamming from one place won't keep the site being spamvertised.
If there's a pattern of this happening and it's not the site owner doing it, then there's a strong paper trail about who is doing it. Getting to the point of kicking someone off is pretty rare, but it is an option in the end for the hosting company if it keeps happening. The hosting company can't afford to get all of its IPs blacklisted, after all, because of a few problem users. Usually this does turn out to be the site owner's own doing, but if it isn't and they still get kicked, it sucks but there are always other hosting companies.