Why does the Qantas website block VPNs?

[Mattg]

Has anyone ever noticed that the Qantas website simply doesn't work if you have a VPN switched on?

I'm genuinely interested in the logic as to why Qantas would do this (assuming it's intentional).

 

[Pushka]

It's been working for me. I'm using Express VPN.

 

[kpc]

I just turned on my VPN...Qf app still works normally.

 

[Be.au]

Perhaps Qantas has received a lot of DDoS traffic from customers using your VPN?
Perhaps Qantas has had a large number of fraudulent transactions from customers using your VPN?
Perhaps Qantas sees a lot of automated/bot activity from behind that VPN?

Which VPN service is it?