http://forums.spybot.info/archive/index.php/t-8604.htmlThe entire system is scanned for most malware. However, because of restrictions in the Microsoft APIs (Application Program Interfaces) used by Spybot, the scan from one account does not include the Internet cache or cookies of other accounts
So if you dumped the caches and before scanning with Spybot, sounds like you would get a complete scan.
Also, if you want teatimer activated for all users the instructions are in the link below.
http://forums.spybot.info/showthread.php?t=308(hmm--I wonder if Ccleaner would clean all users caches in one scan--does anyone know?)