Jeff Moden (11/6/2012)
Be real careful using the single user mode. If YOU lose, drop, or close your connection, on of the Web Services will grab the single connection almost immediately and you won't be able to get back in to set it to multi-user without having to find and shut down all the web services or bouncing the server with it in a maintenance mode.
I have considered this and it is a major concern. As part of general deployments to Production, websites are disabled but as far as I know web services remain on. I think it best therefore to disable all web sites and services and run the maintenance scripts then, outside of core hours obviously.