Theoretically, yes. By implementing special logging tools a server can be monitored in general. However, the data flow from and to a certain user needs some more analysis to be done - which CyberGhost VPN explicitly refuses to do. To underline this, the company will always agree to be inspected by network specialists or net activists like EFF at anytime on its own costs.
In case we are ordered to monitor a certain user account by a court in favor of preventing or unweave a crime, we will of course agree. No anonymization service stands outside the law. However, these orders are very rare. CyberGhost VPN itself never got asked up to now. The reason is quite simple: To be able to monitor a single account, CyberGhost VPN needs data about the account in question from the court, which is only available, if the respective owner already is under surveillance.