Australia was able to stem the flow of people on boats through its policy of diversion with few coming now.
But the policy has kept thousands on the islands in legal limbo for years because the Aussies are still giving their migrants the right to use their legal system to appeal for asylum.
The lawyers would definitely be involved if the EU did it, but such a policy might stop migrants from coming in the future.
Australia has the great advantage of NOT being reachable by a land route. That alone simplifies matter immensely.
I’m sure that any of those kept segregated on the islands are free to leave (go back to wherever) anytime they want to. So their whining does not impress.
Giving asylum seekers access to the court system is a huge mistake, no matter where. Activist lawyers and judges have the system rigged such that they make it almost impossible to kick anyone out.