Well, there are also rules about changing the text (editing) of articles.
I could be wrong but I'm pretty sure that applies to changing the meaning or making changes without indicating that said changes were made. Otherwise, we couldn't excerpt, which is, as you know, required for many sources here.
In my case, I used the type of brackets ("[") that are recognized (in both journalism and other forms of general usage) to denote where something has been edited/substituted.