Disclaimer: I am not a lawyer. This information is not a substitute for actual legal advice. In the event of a question or concern about this information seek the advice of a professional.
Long Version:
From
http://thelawdictionary.org/curtilage/
What is CURTILAGE?
The enclosed space of ground and buildings immediately surrounding a dwelling-house. In its most comprehensive and proper legal signification, it includes all that space of ground and buildings thereon which is usually enclosed within the general fence immediately surrounding a principal messuage and outbuildings, and yard closely adjoining to a dwelling-house, but it may be large enough for cattle to be levant and couchant therein. 1 Chit. Gen. Pr. 175. The curtilage of a dwelling-house is a space, necessary and convenient and habitually used for the family purposes, and the carrying on of domestic employments. It includes the garden, if there be one. and it need not be separated from other lands by fence. State v. Shaw, 31 Me. 523; Com. v. Rarney, 10 Cush. (Mass.) 480; Derrickson v. Edwards, 29 N. J. Law, 474. SO Am. Dec. 220. The curtilage is the court-yard in the front or rear of a house, or at its side, or any piece of ground lying near, enclosed and used with, the house, and necessary for the convenient occupation of the house. People v. Geduey, 10 Ilun (X. Y.) 154. In Michigan the meaning of curtilage lias been extended to include more than an enclosure near the house. People v. Taylor, 2 Mich. 250.
If the subjects property was not enclosed within a a fence or other physical border then they / you have exactly the same expectation of privacy that you would have on a public street. A case may be made that due to the conspicuously posted no trespassing signs that the officer were guilty of, and have confessed to, trespassing. This does
not, however, make the evidence they have gathered inadmissible. It has been repeatedly ruled (I do not have the case law easily available) that evidence collected illegally, so long as it did not violate the fourth amendment (officers acting undercover for example). Contrary to popular belief a person does not have to answer honestly when asked if they are affiliated with a law enforcement agency. Answering dishonestly does not constitute entrapment (again, I don?t have the case law easily accessible). The growers
may (extra emphasis on may) be able to charge the officers with trespassing, but that will only fly
if a DA chooses to prosecute, and
if a court does not throw the case out as frivolous.
Short version: if it is not an enclosed area under you direct control (fenced in land, public restroom, hotel room) you do not have a legal expectation to privacy. This is why they can post cameras everywhere on public property, why surveillance cameras are allowed in businesses, and why the news crew can film everything on a public road. On the other side you can also choose to film the police from your yard, or in public, and they are not supposed to have a legal recourse. Additionally anything they do film you should have equal access to,
if you know to ask for it, and what to ask for, but they do not have to divulge that they have suck recordings.
Warrantless GPS doesn?t fly because it is a form of active (for lack of a better term offhand) tracking that can impede on private spaces (curtilage) How often do you take your phone into the bathroom? Or your car into / onto private property (a fenced in yard for example)? Simple use of a public areas (road and parking lots for example) does not constitute probable cause. Surveillance cameras are a passive (again I lack a better term offhand). They do not appreciably move, and record everything in their field of view, not just you specifically.
Shorter version: The judge made the corect legal call, even if it is a potentially questionable moral / ethical call