Well, as stated in post #3, and reinforced in post #7, it was after the step in the link where you are instructed to restrict the editing.

So here's what I did.

I opened a blank document.
I went to the Developer tab.
I inserted a text field as shown in the highlighted picture.
I double-clicked on said text form and changed the options as instructed. Bookmark was changed to "customername" (once I tried not changing this, no difference in end result), and I checked the "Caclulate on exit" square.
I closed the window by clicking "OK".
I went back to the Developer tab and entered a REF field.
I went through the steps to restrict editing. checking the box instructed and so on.
Everything described above disappeared.