Let me set the record straight on CZ DA/SA pistols.....since I compete with and carry them and have dived deep to understand exactly how they work.
Carrying with the hammer on the "half cock" notch is 100% safe. That's where the hammer stops when you press the decocker on any CZ so equipped (75BD, P-01, SP-01 Tactical, P-09, SP-01 Phantom, etc).
Manually lowering the hammer to that notch on a non-decocker CZ is also perfectly safe because that notch is the same on both hammers. The difference between hammers is an additional surface for the decocker to act upon.
All of the above assumes we're talking about CZs with firing pin blocks, so basically anything that isn't a Shadow. I would not carry a CZ without a FPB at half cock. If the hammer slips off that notch on a drop, the pistol is likely to fire.