The solar panel example is not a loophole. It is a feature. A loophole would be an unintended side effect of designed behaviour. People who pass laws have intent; the courts interpret the meaning of the law and try to divine that intent; a loophole is where a law was passed to prohibit a behaviour but was poorly drafted and leaves a gap for someone to carry on doing the otherwise prohibited behaviour.

I agree that drawing a line is tricky. Certainly people are law abiding unless they are not obeying the law. But that doesn't stop me asking if people are obeying the letter and spirit of the law, and forming an opinion based on the result.