This doesnt surprise me as friends/family travelling on business/pleasure often find all QF flights domestically with no spare seats.
Also the city-flyer service often has a full 737-800 when it should have a B767-300 at minimum to absorb the overflow.
The city-flyer service during peak periods is supposed to have B767's running every 30 mins between MEL-SYD-BNE but this isnt always the case.