Actually it is entrapment, however law enforcement claims that since they advertize the time and locations of the entrapment locations in the paper or on the radio this gives them the right to do it. However an good lawyer will get any charges dismissed that are a result of a roadblock type stop, but most people just plead guilty or hire a sub standard lawyer. In fact officers cannot even legally pull you over unless he has good reason to think you are breaking the law in some way and must show cause to stop you and if he cannot any charges as a result of said stop must be dismissed as well.