Publications are not allowed to check users' browsers for the presence of ad blockers in the European Union.

While publishers are struggling with ad blockers and users, tools to ban them may be outlawed in Europe. Part of the reason for this was a letter from the President of the European Commission, which could serve as the beginning of an open struggle between developers of ad blockers and publishers.

Initially, the head of the company Think Privacy Inc. Alexander Hanff wrote an open letter to European Commission President Jean-Claude Juncker asking for additional clarification of some points on the electronic security directive regarding Cookie.
')

“This law applies only to Cookie or affects any information that is stored on users' equipment and is part of their life and also needs to be protected”, - excerpt from the letter of Alexander Khanff.

The European Commission's response was unequivocal - the sites are obliged to notify users about scanning any information located on users' computers. In fact, any user data is protected under this directive, which means publishers are required to notify and request user permission to scan a computer in order to detect an installed ad blocker.

In most cases, user browsers are scanned using JavaScript and collect information about the configuration of user equipment. In the request of Hanff, there was a mention only regarding the scanning of user equipment, but in the response of the European Commission there is a mention of a ban on scanning from the server side as well.

In fact, users can sue any publishers that prohibit the use of ad blockers to view content on their website. Moreover, according to the directive on the protection of user data - the results of this claim are initially determined in favor of the user. This precedent can fundamentally change the approach to banning the use of ad blockers when viewing content on a site and lead to a wave of collective claims against major publishers.