"Enter the address in Austria where you will spend the compulsory quarantine if necessary," the form for travelling to Austria requires. Most people from Slovakia stop right there.

Filling out the Pre-Travel Clearance form is required along with a vaccination certificate or negative Covid test result before entering the country. Austria is thus overseeing the people who have entered its territory, what means of transport they have used and what they are going to do in the country.
Only people who own property or those who have paid for a stay there can give genuine information in the form, though. The potential quarantine address must be within the territory of Austria. The Pre-Travel clearance form does not need to be filled out by people who are only transiting through Austria or those taking someone to the airport and returning to Slovakia directly after.
Cannot be left blank
People who cross the border just for shopping or for a day trip have a problem filling out the form. The electronic form cannot be submitted with some of the information left blank.
A foreigner moving around Austria without the Pre-Travel clearance form faces a fine if checked by the police. The Austrian Embassy in Bratislava stated that the quarantine address is a compulsory field and needs to be filled out.