I don't see the point in that.
Not every diver wants to "use" his highest certification at all moments.
E.g. my buddy is (aside from GUE diver) a PADI Master Scuba Diver Trainer.
However, he almost never takes his highest certificate with when going on holiday. Why not? Because several times he got "hired" (for free) by local dive shops to help train/guide inexperienced divers once they know his level.
Nice? not really when you're on holiday and want to spent time diving together. Therefor he only takes his AOW + some useful specialties certificates along with him.
EDIT: I agree with this. On vacation I dive on my AOW card even though I have a higher certification. On more than one occasion I was asked as a DM to "bring up the rear and watch the group" because there were too many divers for the DM / Dive Guide to "control". I did once and it ended up where I had to react to a situation which could have ended up a rescue or worse. I will always watch for a bad situation, but I won't be put in the position of HAVING to be a nursemaid.
Cheers - M²