adding reference to class library

I have a class library lets call it UtilityLibrary.

I have a console application. So I right clicked on my solution and added an existing project (UtilityLibrary). I noticed that I can change the code of UtilityLibrary from within my console application.

The issue is if I had added UtilityLibrary to another application and the code had been changed it could causes issues. I was trying to avoid adding a dll reference so thought I would add a reference to my project however I am worried about the code being edited.

Have I added the reference to my project incorrectly?

via Chebli Mohamed