Question: What's the current law/rule on the police taking your cell phone and "reading" the contents? If a policeman asks you for your cellphone do you have to give it to him? bonus question: can you video the cop if he stops you?
Reading the contents of a cell phone falls under Fourth Amendment protections, so in order to examine the contents of a person’s cell phone an officer either needs a search warrant, probable cause under exigent circumstances, or permission from the person who has lawful control over the phone.
A search warrant and permission are pretty clear, but probable cause under exigent circumstances is sometimes misunderstood. The officer not only has to have a reasonable belief that the phone contains evidence of criminal activity, there must be exigent circumstances under which the delay in obtaining a warrant would pose a reasonable risk to safety of persons or the preservation of evidence.
For example, if a kidnapper dropped his cell phone at the scene of the abduction, the contents of the cell phone could be examined without a warrant because of the urgency of rescuing the victim. On the other hand, if the victim was rescued and the kidnapper’s cell phone was recovered from his pocket upon his arrest, a search warrant or the kidnapper’s permission would be needed to examine the contents of the phone.
It is up to you whether you want to grant an officer permission to view the contents of your cell phone. Be aware however, that even when officers have probable cause for a warrantless search they commonly ask for consent anyway. So the officer might view the phone even if you say no, but the burden is on the officer to prove in court there was probable cause to do so without a search warrant or your permission.
Case law is still being established regarding this topic.
You can videotape an officer on duty under most circumstances - as long as the officer is performing his duties in public and the videographer is also either in public or on his/her own private property or on private property by permission of the property owner - but there are some exceptions. An officer may control the immediate surroundings and movements of a person who has been lawfully detained. For safety reasons, an officer will not allow a detained person to hold an object in his or her hand, or engage in activity that hinders or distracts from the lawful purpose. That does not prevent a bystander from videotaping the officer, but again for safety reasons, the officer can order bystanders to move back a reasonable distance.
The other exceptions have to do with protecting the identity of undercover officers, witnesses, informants, and the integrity of an investigation. A citizen will not normally encounter those circumstances, especially when interacting with a uniformed officer. Nevertheless, if an officer directs you to stop taping it is best to first comply with the direction and then request to speak with a supervisor if you feel the officer acted inappropriately.