Criminal Law Questions? Ask a Criminal Lawyer.
Yes. Miranda warnings are to be read to spoken to a suspect once in under arrest/custody and before the suspect makes any statements.
The police do not have to notify a person of their rights before entering a premises. They do, however, have to have a warrant or probable cause to enter.
Probable cause is a sufficient reason based upon known facts to believe a crime has been committed. Probable cause must exist for a law enforcement officer to make an arrest without a warrant, search without a warrant, or seize property in the belief the items were evidence of a crime. While some cases are easy (pistols and illicit drugs in plain sight, gunshots, a suspect running from a liquor store with a clerk screaming "help"), actions "typical" of drug dealers, burglars, prostitutes, thieves, or people with guilt "written across their faces," are more difficult to categorize. "Probable cause" is often subjective, but if the police officer's belief or even hunch was correct, finding stolen goods, the hidden weapon or drugs may be claimed as self-fulfilling proof of probable cause. Technically, probable cause has to exist prior to arrest, search or seizure.
I don't believe that burning incense is probable cause in the usual circumstance, but subjective circumstances could make it enough to stick.
As I said earlier, probable cause is very subjective (case by case). If the officer knows what mj smells like, and he thought it was coming from your room, then the court may agree that he had probable cause.
If you were placed under arrest or put into custody, you should have been given your miranda rights - if not, anything you said cannot be used against you.
It is not improper for the officer to ask you to make a statement, but it should be asked after you've been read your rights.