On the administrative side, I often have to reopen closed work orders to enter purchases or correct problems. This sends an email to the requester in most cases that their work has gone from Closed to Complete, then again when I re-close it. I can only imagine this generates some confusion.
I suggest creating an "Open Admin" status that work orders that need corrections or purchase entry could be placed in. I think that it would alert the requester that the WO has indeed been reopened, but only for administrative purposes, and no further work is being performed.
This would also be useful for running a report to sweep up anything in this status, because as much as I'd like to say I always remember to re-close WO's, our volume is sometimes very high and I know I miss some.
I'm sure there would be other useful applications for this status, but it would help us with our customer communication as well as being an instant flag that something has been reopened by an admin.