Voice Control and phone lock

Hi everyone,
I was testing my new iPhone 4 while I noticed that, despite the fact that there's a passcode set in order to use it, Voice Control still works.
So even if a person does not have the passcode, the phone is allowed to make calls, play music and do everything Voice Control allows.

Isn't that.. wrong?
Or am I missing some different angle for this function?


Regards,
M