Been having a read, and as far as I can tell there is nothing in the legislation that prohibits flying model aircraft right up to the boundary fence of an aerodrome, even in controlled airspace, provided its not above 400ft. (And the other points regarding approach paths/creating an obstruction etc are complied with.)
Happy to be corrected if you can point me to the relevant legislation, I'm all for (responsible) model flying, but this doesn't seem ideal.
101.070 Operation in controlled airspace
(1) A person may operate an unmanned aircraft above 400 feet AGL in controlled airspace only:
(a) in an area approved under regulation 101.030 as an area for the operation of unmanned aircraft of the same kind as the aircraft, and in accordance with any conditions of the approval; and
(b) in accordance with an air traffic control clearance.
Penalty: 50 penalty units.
(2) An offence against subregulation (1) is an offence of strict liability.
Note: For strict liability, see section 6.1 of the Criminal Code.
101.075 Operation near aerodromes
(1) A person may operate an unmanned aircraft at an altitude above 400 feet AGL within 3 nautical miles of an aerodrome only if:
(a) the operation is permitted by another provision of this Part; or
(b) permission has been given for the operation under regulation 101.080.
Penalty: 25 penalty units.
(2) A person may operate an unmanned aircraft over an area mentioned in paragraph (3)(a) or (b) only if:
(a) the operation is permitted by another provision of this Part; or
(b) permission has been given for the operation under regulation 101.080.
Penalty: 25 penalty units.
(3) The areas for subregulation (2) are:
(a) a movement area or runway of an aerodrome; and
(b) the approach or departure path of a runway of an aerodrome.
(4) A person must not operate an unmanned aircraft in such a manner as to create an obstruction to an aircraft taking off from, or approaching for landing at, a landing area or a runway of an aerodrome.
Penalty: 25 penalty units.
(5) An offence against subregulation (1), (2) or (4) is an offence of strict liability.
Note: For strict liability, see section 6.1 of the Criminal Code.