It would seem that this security hole would be an extremely serious flaw for people such as independent researchers who have co-workers who could have access to a computer during time periods that the rightful user was off duty. Bosses could easily "spy" on their employees, which would be a minor issue; but it would also open the door for peers to "spy" on peers and access/steal information that they are not authorized to access. I can see an angry worker accessing a co-worker's computer and modifying saved documents such that the rightful user selects a document by file name and sends it to a client with a completely different message from the original. (original message: "we would love to meet with you and discuss terms." modified message: "we would love to meet with you and screw you royally.") This security hole could, and should, kill the operating system for use by a particular company or in a particular environment. I am surprised that this hole has not gotten more publicity than it has.
Win7: Security Hole 'Unfixable', Experts Say / Infopackets.com
Win7: Security Hole 'Unfixable', Experts Say / Infopackets.com