Nice tips scorpion!

People, don't let karmaxul downplay the threat of thermal imaging and credit card purchases. The police (they own helicopters, dont have to rent) make periodic scans for residential houses emitting large amounts of heat. Karmaxul is right, they cannot obtain a warrant on this alone, but now they are suspicious of you, so they check your credit card purchases. Interesting, they find a 1000W HPS, a CO2 generator and a scale. Now they are really suspicious, so they search your trash and find suspicious refuse. Now they definately have probable cause and will obtain a warrant easily.

Little things add up. Play it safe and do everything you can to not draw attention.