Nice idea cattletruck, but when do you test it? And then what do you do if it passes and you have no more specimens? It also becomes a race between your structure and the specimen to see who fails first, and I am sure Murphy would have a hand in the answer to that question.
There are accelerated tests which can provide a strong indication of the durability of adhesive bonds. Our experience is that when these tests are used, processes which satisfy acceptance criteria and are implemented correctly simply do not fail. As I have said a number of times, our experience was that we turned around a 43% bond failure rate to less than 0.1% and in each of those 0.1% cases we could clearly identify where the technician took a short cut.
My message is that if the processes are CORRECTLY validated, then the current regulations (including the EASA change proposal) are valid and so is NDI, because the interface will not degrade and you will never see mixed-mode or adhesion failures.
It is far better to avoid the problem altogether than try to manage it as the structure weakens around you.
Regards
Blakmax