It is not uncommon to do that, especially in a long survey and in a long survey to have several questions like that. Some people get lazy during a long survey and/or really don't even care about the survey and are doing it for the compensation and will just click answers without reading the questions. If there is a question that says "For control purposes please click 7" and the person clicks 3 it is obvious they aren't reading the survey.

The companies are paying a lot for those surveys and want the most accurate data possible and if someone is answering control questions wrong, they should be disqualified.