How do sister cities work?

Question

I've read about sister cities (usually they are different cities in different countries that have an alliance for something. How exactly do they work? Do they make it easier for citizen to move to the sister city?

Answer 1

It's basically a public relations stunt. Some officials from one city go to the other, exchange a few gifts, and go home. Sometimes there is an exchange of cultural ambassadors -- the orchestra comes to the other town or something, or an art exhibit goes the other way.

I've never heard of it having any legal significance.