The reality is that most people who smoke/vape indoors will lie about it. I've witnessed this hundreds of times from hundreds of people. In every place I have lived I had neighbors who smoked (illegally) and lied about it to my face until I saw them doing it. I would bet that the system is 98%+ accurate and we are seeing the (many) false positives.

Obviously hotels should not use these unless there is some higher accuracy appeals process, but as a nonsmoker I do wish that there were universal and near certain fines for smoking indoors.