1. i'm pretty sure that the MODS are taking care of those posts as soon as possible.
2. i don't think there are enough mods to take care of EVERYTHING on this site...
3. what makes u think that the police is not the one making those ads?
4. when you see one of those ads or anything else that shouldn't be on the site just click the "Flag as offensive" link at the bottom of that post. That goes for all of those posts that violate the sites ToS and Rules like the Classified ads for some "company" from UK that sells brand new iPhones for 1500QR (FAKE!!!) or the spamming posts with the Oakley Sunglasses (2 posts on the same subject with some links inserted there)