i.e. does this call:
NSString *udid = [UIDevice currentDevice].uniqueIdentifier;
return always the same UDID when it is executed on the iPhone Simulator on any mac computer or not?
Currently the iPhone Simulator on my computer returns "2BA99337-3AE2-5234-93DA-193703B876F8".
My UDID is reporting as 03B41D62-FB69-5B6D-A95E-473842F4DFE3 from the iPhone Simulator, so it looks like you're correct.