I have some parameters in a format that need to update when the format is used in a drawing. At the moment I have the parameters in a table allow them to be updated (in a note they don't seem to update and can't be used in a drawing, though they can't be changed). The parameters themselves can't be changed, but they can be deleted from (or replaced by similar text) the table, and then the entire table can be deleted.
You threaten the employee that does this with termination papers
Seriously, I don't know how you can avoid such changes. You can help by creating locked layer or maybe a read only external reference. Normally it is enough to have policies in place to prevent "shortcuts" just to throw the job over the fence for the next poor sap who has to figure out what happened.
If you are doing a check function, however, you can probably toggle the symbols and see if this was changed. I'm sure that certain modelcheck functions can throw warnings too if needed. I am not one that believes in significant automation so I might be the wrong guy to comment.