As noted in a gnucash-user thread here: https://lists.gnucash.org/pipermail/gnucash-user/2018-February/074454.html, there are several toolbar buttons (and menu entries) which allow for the direct editing of register entries in the special A/R and A/P account registers used by the business features which can produce problematic results.

Similar to the option to enable special business feature buttons, there should be the option to disable buttons/menu entries to prevent the direct editing of these accounts. (these functions should not be removed entirely, as some may have use for these accounts without using the business features and may need or desire direct editing and are aware of the consequences)

So far, this is the list of relevant buttons/entries:

Buttons:
Duplicate
Delete
Enter
Cancel
Blank

Context Menu & Transaction Menu Entries:
Duplicate Split
Delete Split
Remove Other Splits
Enter Transaction
Cancel Transaction
Blank Transaction

There are also three additional Transaction Menu entries that may be candidates:
Void Transaction
Unvoid Transaction
Add Reversing Transaction