There doesn't seem to be any good reason to change the rules. Everybody who has the two together railcard understands the conditions of use, so they can expect to be treated as travelling without authority should they wilfully breach those rules. The only justifiable exception I can see would be where one of the persons covered by the card is taken ill during the journey, when the other person may reasonably ask for the ticket to be authorised for use outside of the agreed conditions.
Any other deviation should be dealt with by a refund and a rebooking at the earliest opportunity if a penalty is to be avoided. Trying to find loopholes (that don't exist) can only put the perpetrator at risk of a penalty or worse, although it might make for interesting discussion on a thread such as this.
The conditions of use are quite clear, so if one doesn't like them, the railcard clearly isn't suited to their travel needs.