I disagree. They are there for various purposes (e.g. ECC) that need to be able to have scsi paths to them from host level. Although YOU may not be using one of these things others are and having the OS prevent access is a bad idea. They aren't really that hard to ignore yourself and you can use tools like fdisk to quickly determine which is a gatekeeper as opposed to a LUN of a given size. You typically have to do that anyway unless you're presenting all your LUNs the same size all the time.