Even with the control mode to VAL_INDICATOR, the "typing" cursor also appears. While that makes no sense from an input point of view, a person might want to select and copy the contents of the control.
Another thing to consider is whether you have a consistent and obvious color-coding scheme for controls in indicator mode vs those that are not. That alone can make it obvious to a user not to expect to be able to enter anything. Sometimes people make their own UI color schemes that bury the default distinction between control in indicator mode or not.
If you are still determined, one possibility is "Extended Mouse Events" (Programmers Toolbox). That should give you mouse coordinates that can be compared to the control's size and location, and you may then be able to override the cursor/pointer. I've never tried this - perhaps someone can confirm or refute this as an option.
Hope this helps,
Ian