The recent ruling was based on a case in which an employer changed his on-call service system to establish an emergency service system. In order to do so he demanded to get access to the private mobile phone numbers of all employees. Two of the employees refused to comply with the request which resulted in written warnings. The employees filed a lawsuit with the objective to have the warnings erased from their personnel files.
The issuance of the private mobile phone number constitutes a strong invasion of the constitutionally granted right to informational self-determination. As such it can only be justified by a legitimate interest of the employer. The mutual interests of both parties have to be weighed against each other and come to the conclusion that the invasion is reasonable.
The assessment has to be made with regard to the fact that the constant availability robs the employees from the possibility to distance themselves from the employer’s influence without justification. That prevents the employees to recover and come to rest. The probability to actually be called is not a factor to be considered.
In the given case the employer’s interests did not outweigh the employee’s interests, especially seeing as the employer caused the problem by changing the running on-call service system and since there were other options to ensure an emergency coverage at hand.