From my experience I've never seen problems with links of the approved users.
On the other hand it's very easy to recognize spam post of new users; either I highlight the URL and see the spam link or I follow the link and look over the website. If it is a spam posting, it will be deleted and the user banned forever.
Some times spamer try to post something which looks like nonsense but without a link and they hope to get the "approved" status by the time. In this case I send them a warning pm and I didn't see them coming back with other trial postings.
A wise decision of the administrators has been, to limit the time for users to edit their postings. Therefore it is impossible to insert spam links within the posting many days or weeks later.
Perhaps Clinton or Harry may consider to extend the time limit to 24 or 48 hours. Sometimes users complain about the current short time limit. And I think none of the approved users will abuse such an extended time limit for spam.