A drowned person, a burned person, or a person whose body remains suspended or exposed may not have an ordinary grave. How, then, can there be “punishment of the grave”?
The answer is that the expression is not logically restricted to the physical location of burial. The issue concerns the postmortem intermediate state, and the outward position of the body does not make that state impossible.
These examples illustrate why the name commonly used for a doctrine should not be mistaken for a necessary condition governing every possible case.