Are they to be trusted?

Hello forum members,

Some people do not like tracking cookies, and then they wonder for instance how to block the DoubleClick ad serving cookie? When your browser visits a web site that uses the DART technology for ad serving, you are dealt out a test-cookie, reading test_cookie=CheckFor Permission. If the cookie is accepted you will get a anonymous unique ID number that is stored as a txt file in the cookie dir of your HD. Each webpage you visit using the DART technology will be recognized by DoubleClick.
My question if you go to the opt-out page for thee and similar adware at; http://www.networkadvertising.org/optout_nonppii.asp
must you trust them on their nice blue eyes, and is the opt-out really opt-out. Who knows the answer?

polonus