The doctrine is also regularly used by Transportation Security Administration officers while screening people and property at American airports.
[6] In Horton v. California,[7] the court eliminated the requirement that the discovery of evidence in plain view be inadvertent, which had caused ambiguity.
[11] The Horton ruling also clarified that the officer must have a "lawful right of access" to the objects to seize them under the plain view doctrine.
Investigators must normally obtain a court-issued warrant before seizing property, by presenting enough evidence to a magistrate judge to meet the probable cause requirement.
[13] When using the plain view doctrine, investigators must possess the evidence needed to meet the probable cause requirement, as they are only exempt from the step of obtaining a warrant from a judge.
However, the Supreme Court ruled that lifting the record player constituted an additional search (although a relatively nonintrusive one) because the serial number was not in plain view.
[17] In Arizona v. Hicks, the police officers were in the apartment under another exception to the warrant requirement, exigent circumstances.
This qualified as a lawful entry, and the plain view doctrine applied to items that the officers could see in the apartment and readily identify as contraband or evidence without further search.
[18] These doctrines are also limited to seizing an item when its nature as contraband or evidence of a crime is "immediately apparent."
In Minnesota v. Dickerson, a police officer felt a lump in a suspect's pocket during a lawful frisk search.
The Supreme Court held that this additional inspection was not covered by the plain view doctrine, and as such, the contraband could not be used against the defendant.
Although the warrant was specific to evidence of the murder, the Ninth Circuit held that the plain view exception allowed them to seize the child pornography, as searching graphics files was valid under the warrant and the files were immediately identifiable as contraband.
"Computers as Castles: Preventing the Plain View Doctrine from Becoming a Vehicle for Overbroad Digital Searches".
RayMing Chang, Why the Plain View Doctrine Should Not Apply to Digital Evidence, 12 Suffolk Journal of Trial and Appellate Advocacy 31 (Spring 2007)