[tialaramex]

This is differently bad because it may mean tight loops are enormously slower under debug for no good reason, it's an adverse consequence of the C++ "wrong defaults" problem. Because they're defaults, we can't detect whether they're what was specifically needed or just nobody cared, so we guess nobody cared and act accordingly.

[pjmlp]

It isn't as if Rust is any different in this regard.

[tialaramex]

I'd argue exactly the contrary. In Rust you went out of your way to write the unsafe thing because that's specifically what you intended. As a result there's no need to try to guess whether this code doesn't care, if it didn't care it would be checked because that's the default.