Senator Steve Fielding's personal website has the Commonwealth coat of arms (in a poor quality Jpeg) on the left at the top.
I thought that the coat-of-arms is only allowed to be used on official parliamentary pages and other Commonwealth documents/property, NOT on personal web pages. I checked a number of other senators and didn't find it used on their personal pages. Then I found this site with information about the proper use of the coat of arms.
"Use of the Commonwealth Coat of Arms without permission may be in breach of Sections 53 (c) (d) and (e) of the Trade Practices Act 1974, Section 145.1 of the Criminal Code Act 1995 or Section 39(2) of the Trade Marks Act 1995."
"The Commonwealth Coat of Arms is the pre-eminent mark of Commonwealth authority, power and function. Its use, with a few limited exceptions, is limited to the Commonwealth Parliament, the Australian Government and the Federal Courts. The Arms are not in the public domain."
"Permission to use the Commonwealth Coat of Arms in other than the context of denoting Commonwealth authority and property, is granted by this department, on a case by case basis, but usually in only two circumstances, to sporting teams representing Australia in international competition, and for educational purposes."
Okay - it's likely a mistake made by an over-eager first time Senator, but I think the problem has arisen before on campaign leaflets (with other senators in previous elections).
Compared to the money currently being wasted in unfocused attempted bribes of the electorate in this campaign I reckon its a minor infraction.