as a minor, they can do whatever the hell they want. as an adult, you technically have rights to privacy, in practice, you're still screwed
Yes, it is generally illegal to search through someone's bag without their permission as it violates their right to privacy and property.
If its not theirs they need permission from higher authority (Warrant)
Under certain circumstances, yes, they can.
In general, the police can search your roommate's room without their permission if they have a valid search warrant or if there are exigent circumstances, such as the presence of evidence that could be destroyed or a threat to public safety. It is important to know your rights and consult with a legal professional if you have concerns about a search.
In certain situations, YES.
no he needs a search warrant
If you are suspected of shoplifting, yes. They usually have an officer present however.
Yes, it can be for their own safety as well as other reasons. A person in custody, minor or adult, must be searched before they are booked. Seeing an officer does not need permission from a parent to arrest their child, a search without the parent's permission would coincide.
Only if you let them. If they don't have any warrant, they can only search you IF they have your permission.
Animal control can get a warrant to search and seize animals that are distress.
If a vehicle is searched without the permission of the owner, the officer must have some other justification for the search. This can be probable cause, search incident to arrest of an occupant, inventory prior to towing, abandoned vehicle, or other reasons. If you can show that none of the these circumstances existed when the search was made, you may be able to have the evidence obtained from the search suppressed in court.
No, they cannot search you without good reason (which could be things like not walking straight) or your permission.