Defining and Non defining Relative clauses

Solution 1:

With commas it makes a different sense. The commas show that the writer wants you to lower your voice when you say ",who shouted in the street," because the writer wants that to be additional information. The writer could have written "The children were not from our school. They shouted in the street," but that would not be so neat.

If you are the writer, and if you want that meaning, you can put in the commas, and the reader will lower their voice and make it a Non Defining Relative Clause.

But, if you are the writer, and you want a different inflexion, (Oxford Dictionaries inflexion .2.) and you want a Defining Relative, then you must leave out the commas.