Hi Smaiello,  I totally agree with Joseph. In order to avoid any issues (data loss) and for the fear of punishment, first just remove the device from the SG and then if you are sure that you don't want/need any more the device, then unmap it and unbind it as Joseph said.  Now regarding the ESX, before remove an EMC device from a SG, which device is provisioned to an ESX host, you have to do the following steps: 1. First unmounts the device from the ESX host 2. Detach the device from the ESX console The above two steps can be done via vSphere or ESXCLI.  By following this way you are sure that you would NEVER have ghosts devices in your ESX and dead paths that probably could hang your ESX.
I have attached an image, we have our VMax setup and we are "organically" learning by clicking. When we remove a disk from a disk group and  "unmap" = Dead path for our VMware servers, we have to reboot our VMware servers in order to remove the path  and   "unbind" = We loose data we are simply not able to recover it  I did some searching online but there was no clear explanation of these two terms. What exactly is going on when you select these options.  Thank you kindly, Steven
Unmap & Unbind when moving a disk from a Storage Group