I stand to be corrected on this as I am not 100% sure, but my understanding in Australia is that "flatfeet" does not get you exempted. But, the use of custom made foot orthoses is not permited, but prefabricated ones are. Apparently (and I not 100% sure) is that this has to do with resupply in a combat zone. Obviously prefabs can be resupplied immediatly, but custom made can't. I understand, that prefabs were part of the shipment of supplies that followed Australian soldiers to East Timor a few years back (and presume elsewhere). Anyone know about this?

 

Good for his arches. Pity it wasn't his moral fibre.

 

You are correct in that having persciption othotics does not stop an Austrlalian Defence force member form being deployed. It will affect the areas a member can be deployed to as they need to have access to medical re-supply.
With non-pescription othotics no restrictions on deployement exist.