system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] Why has Batman never attempted to put The Joker in the Phantom Zone?

Batman won't kill the Joker because he thinks that that is wrong yet the Joker escapes from Arkham every time he is put there and could probably escape from most conventional prisons. The Joker kills so many innocent people every time he escapes, Why don't Superman and Batman get together and put Joker in the Phantom zone? It would save so many lives and no one has to die.
gpt
The Phantom Zone allows the people inside of it to observe the world, it would be dangerous to allow the Joker to do so. 

Also, it is not impossible to escape from it, and Joker has a lot of super-powered friends, and obsessed lackies, that would do anything to get him out of there.