Is preventative screening at Tomorrowland legal?

Federal police are screening everybody who bought a ticket for the Tomorrowland dance music festival in Boom. In all some 400,000 tickets have been sold and the details of all the purchasers are being digitally screened. So far 37 people have been informed that they are not welcome at Tomorrowland.
Chris Stessens

It's the first time that the police are staging a mass screening at Tomorrowland. The police are eager to prevent people they would prefer not to see there from entering the site. The criteria for refusing anybody have not been divulged. Peter De Waele: "We're not refusing bicycle thieves or people known for GBH. We are using the most modern techniques and all dossiers are examined individually. We came to the conclusion there were a number of people we didn't want to see there because they could endanger safety at the site."

Half of all visitors hail from abroad. Foreign ticket purchasers have been screened too and police have employed a range of databanks to ensure nobody who is not welcome will have access.

Belgium's privacy commission says that it wasn't consulted on the operation but that it is starting an enquiry to check the operation is legal. Systematic screening is legal, but the privacy commission now believes that the police are going one step further by staging preventative checks and that is beyond the existing legal framework.