Australia does not have any unlicensed spectrum, at least not between 9 KHz and almost to daylight. 2.4 GHz is a licensed frequency, covered by what is called a Class License. This provides the ability for equipment that meets the technical requirements to be automatically licensed. One of the requirements of the Class License, as noted by the ACMA (www.acma.gov.au), is that you must accept any interference from other parties.
What this means is that you cannot require anyone to not operate on the same frequency as you. They can use their own transmitters, and you cannot stop them. If they want to use a wireless video sender on the same frequency, wiping you out, this is not an issue.
This is why major sporting events stay away from unlicensed frequencies as much as possible. During the Sydney Olympics, I had six helicopters for TV coverage. Video signals were all on licensed frequencies in the 2.5 and 5 GHz ranges, and GPS tracking, telemetry and communications was in the 520 MHz range. Cell phone devices were not used, and are still mostly not used due to frequency congestion. As an aside, during a test, we used telemetry frequency a few MHz lower, but found the GPS was not working well. Turns out 3 x frequency + IF frequency was slap bang in the middle of the GPS transmissions.