Here is a general set of facts similar to a type of arrest is seen all too frequently in Maryland:
The police pull someone over for some kind of traffic stop–speeding, rolling a stop sign, having expired registration tags, etc. The officer comes into contact with the driver, states that he smells marijuana, and orders him of the car. Police search the vehicle and find a bag of weed in the center console. Officer then puts the driver in cuffs and arrests him.
At no point during this whole ordeal did any officer ever read the driver his Miranda Rights! Does that mean the possession of marijuana case gets thrown out? That the charge is going to be automatically dismissed?
No. Miranda Rights apply to statements made by the accused, NOT to physical evidence obtained by the police! If there are no statements made by the arrested, the fact that Miranda Rights were never read is not going to have any impact at all on the evidence in the case or the validity of the arrest.
In circumstances such as these where the police find contraband in close proximity to the arrested–in a car, in their jacket pocket, etc.–they may not ask any questions or seek to obtain any statements from the arrested. The police likely think they have enough evidence, and with probable cause to arrest someone will just charge them and call it a day. In this case there are no incriminating statements made such as “the marijuana is mine” that would need to be suppressed. The fact that Miranda Rights were not read to the arrested is totally irrelevant and immaterial to the case under these circumstances without any statements being made. The marijuana may still be used as evidence (provided, of course, that the search was constitutional!) and the police do not have to read the arrested their Miranda Rights.