I represent many individuals charged with misdemeanor marijuana possession or paraphernalia possession. Most of these cases arise in connection with a traffic stop. The car is pulled over by police, the officer detains all individuals in the car, often asks to search, finds marijuana in the vehicle and then asks whose marijuana is it? Here is where it usually gets interesting. Often everyone denies ownership. The officer then threatens that everyone will get charged if no one comes forward. The result is 4 people charged with possession of 1 small amount of marijuana. How can they charge all four if it clearly is only one person's marijuana? The simple answer is: they can charge everybody, but that does not mean they can convict anyone.
Most people would assume that the owner of the car is the one who would ultimately be found guilty of possession because it's his car. Well not so fast. The definition of possession (RC 2925.01(K)) means having control over a thing, but may not be inferred solely from mere access or ownership. This definition also benefits the other occupants of the vehicle as just because the marijuana was in "reach" of all of those in the vehicle does not mean that they in fact possessed the marijuana.
Often the burden of proof (beyond a reasonable doubt) required to convict someone is not met when the definition of possession is taken into account. The end result is that the marijuana that once belonged to 4 people, is now no ones.