I agree that this is area of concern for privacy. Right now the general standard on what police can use for technology is that they can use the same technology that is readily available to the general public. It isn't an unlimited-means standard.

Thermo-imaging equipment to detect marijuana growers is not readily available, so it cannot be used.

Telephoto lenses can be bought by anyone, so they can be used.

GPS is readily available, so it can be used.

The standard certainly is a moving target. I don't agree with its wisdom, but that is the law as it stands.