wilderness - 8:03 pm on Oct 31, 2012 (gmt 0)

This is a very bad administrational choice.

How would you react if another website redirected hundred or thousands of page requests to your server?

Best practice is to simply deny the visitor (i. e., 403).

Unfortunately, even if you deny the spammers (you haven't provided if their log spammers or forum spammers), the denials and their spam will still appear within your raw visitor logs.