A little payback

By possessing a mage ID card, Daniel becomes subject to Hightower law and its corresponding obligations, such as paying taxes and receiving their protection. 

The mage ID exempts individuals from paying taxes to the mundane world, except for value-added tax. Additionally, mages with IDs are immune to mundane law enforcement as long as they do not reveal the existence of the Curtained World to the mundane world.

However, having a mage ID does not provide absolute protection against assault or death by enemies. It does, however, offer defense against enslavement, which is a severe offense in the eyes of the Hightower. If a mage is enslaved, the Hightower will send a squad of grandmaster mage enforcers to deal with the perpetrator.

Even the Confederation, which is known for its capital of slavery, does not dare to enslave mages with IDs because the Hightower responds harshly and swiftly to any such offense.