I don't really see how an admin could take advantage of this, unless they were watching someone spam eat the entity balls and set their life to 99,999 to trick them into eating a ball that set them over. This would only really effect people who had a death wish =)
Also, you might consider editing the code on your server for the entity ball, you could add a check in the consume function that checks the users current HP and determines if it is above a certain point and returns false if it is to prevent the player from eating a ball that will set them over.
