Question

Law enforcers have the right to seize illegal items when they are legally at a location under the warrant related requirement of

Answer 1

I believe the answer is: plain sight

Plain sight means that the law enforcement could make the seize without conducting research to the owner's private property as long as the law enforcers see the drugs directly during their patrol.
If they want to seize the illegal objects outside their patrol, they have to get a search warrant from the government.