As you are claiming damages, you will have the onus on proving your damages. Just being a day late is not going to justify compensation, let alone hugely expensive fares. You are going to have to prove actual loss.
First, the Montreal Convention is silent when it comes to compensation. If you want to talk about entitlements like compensation which do not considered whether passengers have in fact experienced any damages but instead peanlize delays as a moral harm you need to look at passenger rights bills like EU261 or APPR. What the convention provides for is reimbursement for damages encountered. This could include meals, hotels and new flights. But it also could include lost wages if you can show that you missed work and as a consequence of that lost wages. For some items like lost wages I will concede that there is a higher bar to climb in proving damages. However, for things like meals and hotels the simple fact that you were delayed and encountered those expenses should be adaquate. For flights, it would really depend on what option the airlines gave you. For instance, suppose Alaska booked you on a flight departing 3 days later. Most people would argue that this is an unreasonable arrangement as it results in you accumulating additional damages (i.e. more lost work, more hotel stays, more meals, etc.).
You will face the airline having the defence that they took all reasonable (or possible) measures - where reasonable will no doubt be measured against the expectation of what a "normal" loss for a delay would be. For instance, if you had to be back to settle a contract, and by being 4 hours late, forfeited a $100,000 deposit, it is most unlikely that it would be considered reasonable for an airline to spend many thousands on a last minute walk up fare on a competitor to get you home only an hour late, rather than placing you on their own flight the next day - as the normal expectation of loss for a day late would be limited to an expectation of a day's pay.
Those are arguments they can use in court. But at the end of the day, it is the courts that will decide on the balance of probabilities whether the airline is liable. And small claims courts have found that airlines can be held liable in many instances. There are many instances where putting you on the next available flight is a reasonable measure. A classic example that comes to mind is you have a cruise booked and your flight gets delayed and you are rebooked on a new flight departing after the cruise leaves port. Now I will concede a lot of the case will hinge on how much time you have set aside to make the connecting cruise. But if you are like most people and set aside let's say 8 hours or a day, then yes the airline should as a general principle get you to your destination when possible. In those instances, you could argue that you had a choice as a traveller, either book the next available flight or suffer the significant lost from arriving late. Indeed courts around the world have recognized that airlines can be on the hook for the cost of cruises missed or nights in hotels booked at a destination you were unable to use due to the delay. Indeed, there is a simple principle under the law that we should seek to minimize our damages. It is a logical principle since if we don't minimize our damages, it may be the airlines who are on the hook for even more damages in reimbursement. So yes, paying $3000 to buy a walk up fare can actually be a better outcome for both the airline and the consumer than having to pay out the convention maximum of $10,000+ AUD.
It is also not $10,000 AUD but 4,150 XDR, which is currently about $8,332 - and the full flex Y unrestricted one-way fare filed by Qantas for LAX-SYD is currently $9,647 AUD (plus taxes and charges).
Incorrect. The liability amounts under the convention are reviewed regularly by ICAO and updated to adjust for inflation. In particular, on the 28th of December, 2019,
those amounts increased to 5,346 SDR
which works out to $10,768.68 AUD
Eu261 and DOT and canadian consumer laws bypass all of that.
So yes, Montreal is there. You could make a claim. The airline could argue all sorts of defences. What are you going to do then?
Eu261 is very consumer friendly. You don’t get the same legal issues and risks from enforcing under 261, or aussie consumer law, etc.
In what way are these consumer laws different from the Montreal Convention? At the end of the day, the airline can still deny all of these claims, and you are left with having to go to court. Now maybe you could argue that the burden of proof is lower. But you still have to file paperwork and potentially spend considerable time in court to seek a remedy under the law. After all, these laws are silent when it comes to things like enforcement. For instance, whilst you can complain to the Canadian Transportation Agency (CTA) when an airline denies your compensation and they can certainly investigate and even rule that the airline must pay you, it takes several years for them to do so, with them having a backlog of tens of thousands of complaints they must adjudicate. In addition, even if you are successful with the regulator, all the airline needs to do is
appeal the order in court to have the whole thing set aside.
As for Australian Consumer law, it's the same thing there. Yes you do in theory have rights as a consumer, but it doesn't stop companies from misrepresenting what those rights are and even denying you those benefits. Maybe you could go to the ACCC and maybe if they are inclined to do so they'll even investigate. But we are talking about a long drawn out process where even their findings may hold no water (since again companies can just appeal the matter to court).