Anyone who has even had a sip of alcohol is at risk for being arrested for DUI. For that matter, anyone who has cannabis in their system from using a week prior is at risk for being arrested for DUI. Police officers arrest suspects based upon probable cause only - this can be as little as a minor traffic infraction and the smell of alcohol. Even though this type of case can usually be won at trial, the arrestee has still had a license suspension (summary suspension) and paid thousands and thousands of dollars to their attorney for their trial. The best plan is to not give the police officer any ammunition to use against you at trial. Even if you think you are probably ok to drive, it's best to not answer the officer's questions, not perform field sobriety tests, not perform the street breath test (portable breath test), and not perform the breath test at the police station (breathalyzer). Under the law, the State must prove a defendant guilty beyond a reasonable doubt at trial. For example, in People v. Harris, 2014 IL App (2d) 120990 (May 22, 2014), the Illinois Second District Appellate Court held that the State failed to lay the proper foundation to admit the breathalyzer machine logbook into evidence. An attorney is necessary to protect a defendant's rights before trial, during trial, and even after trial, as an expungement of the arrest may be a possibility after winning at trial.