Answer to Question 1
Fourth Amendment analyses follow a three-step process based on answering three questions in the following order:
(1) Was the law enforcement action a search or seizure? If not, the analysis ends, because the Fourth Amendment only protects actions that are searches or seizures.
(2) If the action was a search or seizure, was it reasonable? If it was, the inquiry ends, because the Fourth Amendment bans only unreasonable searches and seizures.
(3) If the action was an unreasonable search or seizure, does the Fourth Amendment ban its use as evidence? If it does, the case isn't necessarily over, because there may be enough evidence to convict the defendant, either now or sometime in the future.
Answer to Question 2
SCOTUS has decided that thermal imaging and GPS tracking are Fourth Amendment searches. In the case of thermal imagers, SCOTUS concluded that, although there was no physical trespass of the house, the discovery and measurement of heat from a home is a Fourth Amendment search. In the opinion the Court stated when the Government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a search' and is presumptively unreasonable without a warrant..
Regarding GPS, SCOTUS held that the government physically occupied private property for the purpose of obtaining information. Given that the Fourth Amendment protects property, the placement of a GPS tracker on private property constitutes a Fourth Amendment search.