According to the manual (http://cz-usa.com/assets/files/cz75P-07DUTY_en.pdf) you can damage the trigger mechanism:
However, it is not recommended that the safety be engaged while in this state as any forced cocking of the hammer could damage the trigger mechanism. The pistol safety shall be only engaged with the hammer in its rear position, i.e. cocked. The use of safety is therefore convenient for short interruptions of firing only.
Try putting a mag in it...many guns will not fire without a mag locked in...it's a safety thing from old military arms....if you get in a struggle with someone and feel you may loose your weapon you can hit the mag release and the gun is disabled and cannot be used against you.



























