Hi guys.
The koalas your talking about were introduced to that tiny island - not native to it.
So you can look at them like any other indroduced pest i guess. (yeah , i know they are cute)
They wont be letting any tom, dick or harry hunter on there it would be a controlled cull by National parks officers also.
I dont know about zoo's elsewhere but sometimes other zoos dont have room for animals - im sure they would look at that first. But when i worked at a zoo here there were animals kept in tiny cages out the back as there was no room for them and no other zoo's wanted them. (a very friendly gibbon, numerous small critters and birds ect ect).
Koalas are very territorial also. If they just go and plonk a few in another groups area there would be hell to pay.
Just thought id put this info in incase you wernt aware.

These things are slowly starving to death and thier makeup makes it extreemly hard to relocate them.