I have been trying unsuccessfully for some time to get my Oracle Certification Prep site listed as being safe on the CertGuard website. However, I have never succeeded in getting a response back from them. Until recently I simply left it at that. However, a couple of days ago I did some more searching and found several signs that the site has been stagnant since around 2011.
I asked a colleague who writes about certifications across multiple vendors, Ed Tittle, if he knew anything about the issue. Ed did some digging and created an article at GoCertify. I'm not going to recreate here what he already wrote. If you are interested in avoiding being caught out by brain dump sites, you should check out his article.