What i am thinking is an auto death if you try to fly so people can't just hack their way into 1000 meters above the lava and get points. Also if you noclip, you "suffocate" and die. Noclip includes digging down in a superop zone so that the block immediately comes back and you are effectively hidden from the lava. One way for ops to get around this could be to use /invincible so that no deaths result from flying when you are trying to moderate.
Fly death
moving upwards more than 3 blocks at a time (so jumping is ok), staying the same position 3 blocks above ground for more than 3 seconds. Moving downward does not cause death as someone could just be falling from a high height.
noclip death
If a block covers the head of a player for more than 3 seconds or a person goes outside the map boundaries.