No, it is not appropriate for a police officer to threaten you. Police officers should abide by ethical guidelines and use only necessary force or coercion in carrying out their duties. If you feel threatened by a police officer, you can report this behavior to their department.
Trespasser is the term for this. This is illegal and you can be arrested for it. A police officer will not usually arrest someone the first time they are caught trespassing. But it is up to the police officer to arrest or not.
They can threaten you, however, to enact an arrest without probable cause or reasonable suspicion that you've have in fact committed a crime is considered false arrest. If an incident like this occurred, you may wish to file a complaint against the officer with his/her desk sergeant.
There is no such thing as an illegal argument so the illegal police will not arrest you.
It sounds like you're asking an opinion question. In my opinion, yes. If a person is caught with illegal drugs, yes, a police officer should arrest the person.
Yes, of course. An arrest warrant is a command from a judge to arrest a person. Usually a police officer has no choice and must arrest.
A person is "under arrest" when a police officer charges them with a crime and chooses to take them to the police station to be processed for it. For example, if someone commits a crime, they are technically under arrest when a police officer witnesses the crime or has a warrant for the arrest and tells the criminal "You are under arrest." Typical procedure after this is to put handcuffs on the criminal and read them their Miranda rights (you have the right to remain silent etc). Handcuffs alone do not mean arrest, but i'm pretty sure its illegal for a police officer to handcuff someone without grounds to arrest them. As a side note, the person doing the arrest does not have to be a sworn in police officer. In Citizen's arrest cases, anyone with arresting powers like a bounty hunter can also place someone under arrest.
yes
No.
A police officer making an arrest
No, a police officer cannot issue a warrant for your arrest only a judge or court magistrate can do that.
Police's job is to stop the Illegal happenings in their country and if you are an illegal imigrant, (even if you havent happened) and if they found out, yes they would definetly arrest you!