I get the idea of trying to prevent someone from relocating an enemy champ on to a pile of traps on top of a lava square, but this breaks a lot of things, including relocating friendly champs that would or would not be injured. Example, equipping Minotaur Portalwalker with Molten Cloak. Move around, then try to portal to a square with lava. Even though the champ is immune, it fails to do anything. Try swapping a flying champ and you can't, in fact, swap completely fails to work in any situation because it will not swap a champ on to the lava squares that the cloak generates. Also, if I want to take the injury of swapping a champ on to a lava square, it should be allowed.
It would be too strong offesively if it worked how you wanted it. Flying champ over lava *swap* dead non flying champ