FACTS (a): client gets arrested on a drug charge, and the cops want to look at the phone in order to obtain dealer/transaction data (usually in text messages). Client refuses to provide the password (usually a 4 or 5 digit code) to the phone. Client gets arrested and handcuffed. Later, cops offer to permit client to make a phone call to family. Client unlocks phone to make call, cop then grabs phone and searches it now that its unlocked.
FACTS (b): A variation on this fact pattern has been that, once the client is arrested, the cop seizes the phone and figure out it is password locked. So, they offer the handcuffed arrestee an opportunity to make a phone call, only to snatch the phone back once the phone is unlocked. Rude, but true.
Yep, pretty dirty trick. And yes, evidence found as a result of such a ploy will be suppressed, as the search of the phone is clearly unconstitutional. That being said, I still want to warn people that there are deceptive law enforcement officers--if you've read this website much, I didn't even have to say that.
Drug arrests are always intriguing to the police. Every new cop thinks he can track down a Colombian drug lord if he can just get enough information from a white middle class high school kid he just busted for misdemeanor possession of marijuana. Often, police aren't concerned about a misdemeanor amount of weed, they want to know where the weed came from. A familiar line is "Tell us who your dealer is, and we won't arrest you." The problem is, most people who possess drugs are not willing to snitch on their dealer. Cops know this, but they are now armed with tons of personal information via cell phones. Yep, just look at the texts on a cell phone long enough, and you can probably find a drug dealer in there somewhere--assuming the cell phone belongs to someone arrested for drug possession (searching my mom's texts will only lead you to choir practice or Bible study). Searching a citizen's cell phone after a drug arrest is not legal, but it happens all the time.
I encourage everyone (even my mom!) to password protect your cellphone. This can keep the police, and thieves, out of your private business. After all, we Americans value our privacy. When we mail something, we seal the envelope--not because we have something to hide, but because we want privacy. When we go home, we shut the door behind us. We close the bathroom door. None of this is done to hide illegal activities, its done because we want our privacy.
Basically, when law enforcement searches a cell phone without a warrant, such a search equates to a "general evidence-gathering search" and thus a warrant must be obtained. I'll be writing about the search and seizure aspects of this issue in the coming months (i.e., whenever I get around to it). For more details on how this issue has come up in drug cases, check out my article "Cellphone Passwords Protect Against Big Brother's Invasions".