[Phil_Latio]

> documentation clearly states that it's UB to violate them

Only in "fast" mode. The developer has the choice:

> Compilation has two modes: “safe” and “fast”. Safe mode will insert checks for out-of-bounds access, null-pointer deref, shifting by negative numbers, division by zero, violation of contracts and asserts.

[SkiFire13]

> The developer has the choice

The developer has the choice between fast or safe. They don't have a choice for checking pre/post conditions, or at least avoiding UB when they are broken, while getting the other benefits of the "fast" mode.

And all in all the biggest issue is that these can be misinterpreted as a safety feature, while they actually add more possibilities for UB!

[Phil_Latio]

Well, the C3 developer could add more fine grained control if people need it...

I don't really see what's your problem. It's not so much different than disabling asserts in production. Some people don't do that, because they rather crash than walking into invalid program state - and that's fine too. It largely depends on the project in question.