When you start a new drawing with the New Drawing Wizard, CC3 looks for a map note called OnNewMacro. It treats the note as a macro and runs it. It then deletes the note. Usually, this macro will open documentation for the template:
OPENDOC #documentations\thistemplate.pdf
Similarly when a drawing opens, CC3 looks for a Map Note in the drawing called OnOpenMacro. The can do a number of things, for example
Set the current symbol settings
Set the symbol catalog window to display the symbols in the drawing
Display a particular menu
Clear the cache
To stop a template always running the OnNewMacro, delete the appropriate note from the template.
To stop a drawing always running the OnOpenMacro, delete the appropriate note from the template.