In WA any Police Officer can search any person/vehicle/vessel if they reasonably suspect any person committing an offence under the Criminal Code.
They can also search any person/vehicle/vessel if they reasonably suspect any person committing an offence under the Misuse of Drugs Act. Queensland has a very similar Misuse of Drugs Act as WA.
If a Police Officer pulls you over in a known ‘hot spot’ (pretty much anywhere) and ask you some questions and you refuse to answer, then they can search you. You may ask is this ‘reasonable’ suspicion. Can any one spell grey?
If a Police Officer looks in you car and sees an empty clip seal bag then you can draw an inference there were once drugs in the vehicle. Then they can search your vehicle and any person in it. If there is a known drug user in the vehicle same again they can search and will get away with it.
It is also a misconception that Police (in WA) need a search warrant to search your house. In WA if you are under arrest for a crime. Police can search your dwelling with out a warrant. They get this power from Section 58 of the Police Act.
Police still will normally obtain a warrant as it looks more professional if and when the charges go through the courts. If they obtain a search warrant from Section 711 (normally for stolen property etc, not drugs) of the Criminal Code for your house they can also search your vehicle. However, they can not search your person. They can pat search for weapons if they believe you may be carrying.
If a warrant is obtained through the provisions of the Misuse of Drugs Act then they got ya. They can search your body and any person in your house. Also people that come to your house during the warrant.
Police are not that stupid. When putting the 711 search warrant to the Justice of the Peace they must list all items that they intend to look for. For example a Plasma Screen TV. They will list the TV and the remote. This gives them the power to look through small compartments for ‘the remote.’
On a drug warrant they only list drug and there grounds to search.
Anyway, be good, if not be good at it!