I don't see how a stake-out isn't a search. It might presumptively be a reasonable search that doesn't require a warrant, as it's not a search that interferes

I don't see how a stake-out isn't a search. It might presumptively be a reasonable search that doesn't require a warrant, as it's not a search that interferes or trespasses. But they are looking for evidence, right? I call looking for something a search.