In civil legal proceedings the inference switches the burden of proof to the other party. Following the example, if it's proven you have a MJ card, it is presumed you consume and you have to prove you do not by whatever means.
In a criminal proceeding said inference is not permited by the Constitution. You don't have to prove your inocense. The burden of proof to show you are guilty of commiting a crime beyond a reasonable doubt lies on the prosecutor. An inference doesn't fulfill the quantum of proof to establish guilt beyond a reasonable doubt nor can it switch the burden of proof for a man is inocent until prooven guilty.