Ok, I will just close it. It is painfully clear that e.g. `mmap` uses it this way to prohibit closing, and also `memoryview` has all the machinery necessary to do counting of how many exports, etc. exists.

I admit, this still rubs me the wrong way, and I think it means that we may need to check `bf_releasebuffer != NULL` also in NumPy.

We still have the issue of not being able to use `releasebuffer` easily in NumPy. But there is nothing to be done, unless we can consider limiting the `"#s"`, etc. type argparsing, which is likely not an option.