Funny. I'm new to IDPA and ran into the same thing. The SOs that won't allow you to decock are incorrect. Look at the rules and you'll see nothing that prevents it. The CZ75B can compete in either SSP (if decocked) or ESP (if run with the first shot cocked and locked). There is some disagreement as to whether running the pistol is SSP requires a complete decock with the hammer lowered to the frame, or if you can decock only to the safety notch (which is consistent with the CZ decocker models). I think someone on this board is asking IDPA for a ruling on that question. Additionally, there seems to be some issue as to what happens if you have a AD/ND while decocking. Some say you are automatically DQ'ed. Others say that if the bullet isn't within 6 feet, then is not an automatic DQ, but you may be DQ'ed at the discretion of the SO for unsafe gun handling.