A few years back, they spent hundreds of thousands of dollars to nab a retiree over 2 small dried-up plants in his basement.
Because he bought a growlight from a magazine ad, they sifted his trash for over a year, had cameras watching his house, did flyovers looking for heat signatures. They used every thing in their arsenal just to put a 68 yo man with back pain on probation
You have to have a warrant to use thermal imaging on a domicile, which means at that point you can probably apply for a warrant to physically search the house.