May be late since multiplayer will change soon, but... In survival mode on multiplayer, the player who joins onto the server can take a fall from water level all the way to dry bedrock, full speed, without taking any fall damage. This seemed to happen about 4 times out of 5. To reproduce, dig a deep hole, have someone join you, and have them jump to bedrock. The phone is a Nexus S 4G. Thank you!
Andrew, does this look like the same issue as MCPE-1021? Marking as a duplicate of that ticket for now, since others similar to yours have already been marked as duplicates of that one.