I agree that the CZ is a really tough gun, I have used +P in mine for years with no problem, also I have used +P+ ammo in it (about 2,500 rounds) with no problems. The standard NATO 9mm is a pretty hot round as it must function a variety of SMGs.
When you hear about military or para military organizations cracking frames or slides on whatever weapon, remember that those guys literally shoot their guns to pieces. Their traning weapons are fired till literally unusable. Particularly the elite organizations, U.S. Delta Force types shoot so much ammo you simply would not beileve it. It is no wonder they break a gun every now and them. And with the BHP, remember it is a 1935 design, and back then +P was unheard of, along with a lot of other stuff that goes into the chambers of those guns.