Nice thought but not practical. Spammers use different bogus IDs every time they post. These is a way to stop automated spam posters, however, if a spammer takes the time to do it manually, there isn't much that can be done... other than making this site a "paid only" to post site. Some sites control this by requiring that posts be read by a human moderator ( at least the first post from a new member) before getting posted, which would cripple this site. Other sites have a team of volunteer trusted moderators that keep tabs on the forums and delete offending posts. Typically, these are non commercial sponsored sites ( this one is commercial).
The best defense is quick action by this site's administrator. Or possibly a "report this post" button that could be operated only by folks with a high number of posts. IT should be noted that this forum uses "canned" software and the administrator is limited to those features that are "part of the package"