What distinguishes tadlīs al-shuyūkh from ordinary multiple designations?

Narrator Anonymity: Wuḥdān, Mubham, Majhūl al-ʿAyn and Mastūr

• The deliberate obscuring of a teacher’s recognizable identity through an unfamiliar name
• Every kunya is automatically tadlīs
• Every nisba is a lie
• A narrator with multiple names cannot be trustworthy