Scene one: a researcher distributes an online questionnaire on vacation planning habits. He's told that this survey, conducted on Google Forms with 78 people, provides an informational context to know if people verify their papers in advance. The problem is that the sample is small and there's no direct proven link between planning vacations and verifying identity documents. How to know if these 78 people are representative of all travelers? Relying solely on this type of survey risks making decisions that do not reflect the reality on the ground, like a family planning vacations a year in advance but forgetting to verify the validity of their children's passports.