Way to lock derived bookmarks in Word?

I have some derived bookmarks that are based on evaluating other bookmarks with an "if."

Ex.   Bookmark1 = "Male"  Bookmark2={if{Bookmark1}="Male" "he" "she"}

I wanted to programmatically lock these, so that they will not be accidentally deleted or edited.   Their purpose is only for reference when building templates.   I tried putting them inside content controls and locking those controls.   This, it will do.

However, when you open the document, Word throws an error because the derived ones are locked.   I assume it is trying to perform an edit and replace in them and is encountering the lock.

Has anyone successfully found a method to get around this?   Essentially, like Excel, it ought to simply do its internal math just fine, but prevent me from changing the formula. 

Thanks.