I have a virtualized dev machine that is disconnected from the network. I want to add a local user (from the vm) to an attendee list. Can't do it because this user.. being local... does not have an email address. Any suggestions?
If you're on a standalone box you can always create a windows account for the dummy user, then add them to the site as Matt said (WFEName\LocalUserAccount). That should be pretty straight forward; you can add as many dummy users as you need. You must create a windows account for the user before you can add them with this method though.
Not sure if it's just me, but I can't see your screenshot.