I'm not sure I would describe the situation precisely as you have, but
essentially you are correct. Microsoft Antispyware beta1 does not work as a
user would expect in either limited or multiple user/acccount situations.
From Steve Dodson:
You have a limited user account running the application looking for spyware
on all files and folders. This includes the administrator account which
limited users may not be able to access. So we have to approach this
carefully in order to remove the spyware from all locations, but also
preserve file and folder permissions and access.