All questions in the survey can be "skipped" by users if they don't want to answer the question. The option to skip a question in the survey is automatically added to all questions in the survey.
Skipping a question is NOT the same as answering "don't know" to a question, but is used to skip a question that the user doesn't want to answer for one reason or the other. Typical reason to skip a question is that the question is too personal, too long and complicated, badly formulated, irrelevant to the user etc.
The number of users skipping each of the questions in your survey is automatically monitored by the UserReport system which reports back to you, if too many people are skipping certain questions in your survey. If a question gets skipped by more than 20% of the users a red flag will appear besides the question in your survey editor.
If one of your questions get skipped by a lot of people, you should consider to rephrase the question or deactivate it from your survey.
The skip function and red flags are essentially made as a service for you to improve your survey and hence the online experience that your users get when taking the survey on your website. UserReport is meant to be a tool with which to make short and fun online surveys.