I think it's worth pointing out that taking someones code and running it again on the same data does not constitute an independent verification of the original

I think it's worth pointing out that taking someones code and running it again on the same data does not constitute an independent verification of the original work. Just like scientists don't go using the same lab to verify an experiment, they shouldn't use the same code. That said, it is often useful to release code for other reasons. For applied areas, releasing the code in the form of a software tool is fairly common. This allows people from the target area, who may not be computer scientists, easy access to the new method. Code review seems to be nearly non-existent in the scientific community, although it does happen occasionally when one researcher uses another's code base for further experimentation.