Please check again. The rules say you can't advertise other services.

I would recommend that everyone who is concerned that DB is a scam should stop wearing the DB signature completely, switch to some other campaign, and at the end of the month we'll pay you out for the 9 days you wore it for.

Then you don't need to add a disclaimer.

It seems unreasonable to expect anyone to pay you for advertising a site with "this is a scam" tagged onto the ad. Even if the rules don't explicitly prohibit it, common sense does. Why would anyone pay you to say they suck?