I suspect that we may not understand your question! Do you mean being able to block an IMEI from within your online account?
I can see the attraction of being able to do this, eg not having to make telephone contact immediately if your phone has been stolen. But I can see considerable risks as well, as it isn't a process that is easily reversed; at least having to speak to an agent gives them a chance to say "Are you sure you haven't just mislaid it somewhere within your home? Are you absolutely sure?" There is also the danger of someone blocking an IMEI maliciously; although Vodafone UK has introduced 2LA security into the account log-in process, many of us are not as careful as we should be in choosing our alternative numbers, and may unknowingly have left the door open to intruders.
