Because your licence prevents you from moving

You need a licence to do your work.

You live in a large country where, according to the constitution, you may move freely between different cities, different states, different provinces.

In practice, the moment you step across the city limit, the state border, the provincial boundary, you’re subject to a different licensing authority, your licence is no longer valid, and you can no longer do your work.

You need a different licence, though your work is no different the other side of the line.

As a financial adviser, you need a different financial advice licence, though people’s cash flows no differently there.

As a hair stylist, you need a different hair styling licence, though people’s hair flows no differently there.

As a paramedic, you need a different paramedic licence, though people’s blood flows no differently there.

Your work keeps you a prisoner in your own city, your own state, your own province.