Many times police officers will not see anything, especially with pot plants. These are normally hidden away under some type of heating lamp. It does not matter if the police came for another reason, they noticed the odor, and that is all it takes. I hope you were not the one whose house they entered, but if you are, my apologies, they can do so. Even in CA where growing pot for medicinal use is legal, federal agents (The Federal government treats any possession
of marijuana as illegal) have been known to bust the shops and even the users home using probable cause of odor/smell/sense. I would start looking for other defenses other than unlawful entry.
If this was your house, keep in mind that charges are normally based on the amount they found, and if they an establish you had an intent to sell, it gets quite serious then. Probably not what you want to hear, so in turn, you probably are not happy with my answer, which in turns means you may not accept it. I fully understand. Please know I do not make the laws.
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