The documentation info about cancelling a right click event is pretty confusing, so I am going to describe the thing I want done because I do not even know if its possible.
In the Mutant Mobs mod, there is an item called a Creeper Shard, that when Right Clicked, will cause an explosion. The problem with this is that it breaks blocks, even if they are claimed by the FTB Mods, and we do not wan't this on our server.
Using Event Cancelling I have already turned off certain commands in certain dimension, and stopped a type of mob from spawning, but the thing I do not know is that if you can cancel something like an item interaction. If it helps the item has a cooldown like an enderpearl or chorus fruit, so it seems like a basic item interaction to me.