Kam Fook in chatswood, an enormous yum cha place in Westfield, was shut down for a months by the tax office some years ago to go over their books, previously they had the 'cash only' policy with a big sign out the front saying this as you walked in.
Seems to be less common in the last couple of years, especially after the example set with the above restaurant. Couple of places still have this policy though. Maybe small enough to fly under the radar, still worth an email to the ATO when you see one though.
