Minecraft 1.8 Looting Problem

In Minecraft 1.8, when you have a modified mob such as a Zombie Full Diamond with 0% chances of looting, if you add Looting 1 to a sword, the percentage won't remain at 0% but it will get to 1%, and this can be a problem for mapmakers, because players will have a chance of getting a drop that isn't meant to get in that map.

Thanks.