Our team of software developers consists of a bunch of experienced programmers with a variety of programming styles and preferences. We do not have standards for everything, just the bare necessities to prevent total chaos.

Recently, I bumped into some refactoring done by a colleague. My code looked somewhat like this:

public Person CreateNewPerson(string firstName, string lastName) {
    var person = new Person() {
        FirstName = firstName,
        LastName = lastName
    };
    return person;
}

Which was refactored to this:

public Person CreateNewPerson (string firstName, string lastName) {
    Person person = new Person ();
           person.FirstName = firstName;
           person.LastName = lastName;
    return person;
    }

Just because my colleague needed to update some other method in one of the classes I wrote, he also "refactored" the method above. For the record, he's one of those developers that despises syntactic sugar and uses a different bracket placement/identation scheme than the rest of us.

My question is: What is the (C#) programmer's etiquette for refactoring other people's sourcecode (both semantic and syntactic)?