One of the first things we tell clients in our criminal defense practice is never give a law enforcement officer permission to search anything. The Constitution places strict limits on when law enforcement can perform a search, and oftentimes officers won't have a warrant or the probable cause they require when they want to search a suspect's property. However, the moment that a suspect consents to a police officer's search, most of that suspect's constitutional protections disappear. For this reason, "consensual encounters" are one of the most popular techniques that officers use to collect evidence. When an officer asks if he can search a vehicle, he usually is not just being polite, but likely has doubts about whether the constitution allows him to perform a search without the suspect's permission.
If most police searches can be stopped just by telling a police officer "no", this raises the question of why so many suspects engaged in illegal activity allow officers to search them. The simple explanation is that talking to the police is stressful, and many suspects fear they will be retaliated against if they try to leave a police encounter. Luckily, even when a suspect consents to a search, courts will still suppress the fruits of that search if they find that the consent was not "freely and voluntarily" given.
A recent case out of the Third District Court of Appeal, State v. Hall, provides an example of how this works in practice. In that case, three police vehicles pulled into a defendant's driveway and a fourth vehicle pulled up to the driveway to block the way out. The police then asked the defendant if they could perform search, and the defendant agreed. Officers frisked both parties, took their IDs and car keys, and searched the vehicle where they found an illegal taser in the defendant's car.
The court suppressed the introduction of the taser into evidence, because it found that a reasonable person in the defendant's position would not have thought that he was free to leave the encounter. More interesting, the passenger testified that the police never drew their weapons or made a show of force. In fact, the witness stated that the police were polite during the encounter. While the court noted that a mere submission to the apparent authority of a law enforcement officer is not enough to show that consent was involuntary, its holding recognized that police officers do not have to use or threaten violence to violate a suspect's constitutional rights during a consensual encounter.
While the defendant in Hall had the evidence of the search suppressed in his case, it is important to realize that courts will look at all of the circumstances of each search on a case-by-case basis to determine if consent was voluntarily given. Suppressing evidence because of involuntary consent is never a sure bet, and actually only happens very rarely. When a suspect is stopped by the police, it is always easier to withhold consent and ask the officers to leave than to take a chance on the court finding that consent was involuntary.