Within 30 to 45 seconds after Overdahl entered the room, the officer noticed seeds and a small pipe lying on a desk 8 to 10 feet from where he was standing. From his training and experience, the officer believed the seeds were marihuana and the pipe was of a type used to smoke marihuana. He entered the room and examined the pipe and seeds, confirming that the seeds were marihuana and observing that the pipe smelled of marihuana...Tough luck for the doper.The "plain view" exception to the Fourth Amendment warrant requirement permits a law enforcement officer to seize what clearly is incriminating evidence or contraband when it is discovered in a place where the officer has a right to be. Coolidge v. New Hampshire, 403 U.S. 443 (1971); Harris v. United States, 390 U.S. 234 (1968). Here, the officer had placed Overdahl under lawful arrest, and therefore was authorized to accompany him to his room for the purpose of obtaining identification. The officer had a right to remain literally at Overdahl's elbow at all times; nothing in the Fourth Amendment is to the contrary.
U.S. Supreme Court, WASHINGTON v. CHRISMAN, 455 U.S. 1 (1982)