My 2 cents worth:
First up, I think there needs to be a clear understanding of the real difference between such terms as "Australian", "Australian passport holder", and "Australian resident". I am an Australian citizen, and passport holder, but I am NOT an Australian resident.
I use the TRS scheme from time to time as sometimes when I visit the homeland I buy some sort of item or equipment which I take back with me overseas.
IMHO, the TRS scheme is designed, fundamentally, for the purpose of allowing "visitors" to get back the GST on items that are purchased. I do NOT believe that any Australian resident should be able to seek devolution of the GST via the TRS scheme. I believe that such persons should go through a different process that puts much more onus on them to demonstrate why such an exemption should be given to them.