The Latvian government has decided that travelers crossing the Latvian border with commercial travel companies, such as buses, ferries, trains and airlines, will be required to complete a questionnaire from July 16, 2020. See https://www.mk.gov.lv/en/content/covid-19. According to the Cabinet of Ministers, the data will be used to fight against the corona pandemic. So far, the Baltic States have survived the corona epidemic with only a few sick, although the economic damage is enormous. Travelers from countries with more than 16 sufferers per 100,000 inhabitants are still not allowed to enter or have to go into quarantine for two weeks. This quarantine will be controlled by the Latvian police.
The transport company must hand out and collect the questionnaires. Passengers are obliged to disclose the following information to the Latvian authorities: surname, first name, telephone number and home address. At the moment this means that travelers have to fill out a form by hand. The Latvian government plans to replace the questionnaire with an electronic form in a few weeks. Of course, this makes it easier for the Latvian authorities to evaluate the contact details.