This is correct (and I am using “invalid” here in a semantic sense, it is still structurally valid). There are a number contexts in low-level systems code where a static proof is not possible even in theory, so there needs to be a way for code to inspect object validity at runtime. Process address space isn’t entirely private, external actors that your process doesn’t entirely control can modify it e.g. via DMA.

The C++ compiler largely assumes that such static proof is possible by default and has no way of knowing if it is not. To address this, the C++ language has added features for annotating objects to indicate that static proofs of state are not possible at compile-time (e.g. std::launder).

Database kernels are the most extreme example of this because most objects in the address space don’t own their memory address and the mechanism that temporarily puts an object at a particular memory address is not visible at compile-time. Consequently, object location and state has to be resolved dynamically at runtime.