While reading the PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH section of some completed NSF award abstracts, I expected to find papers only within the limited scope of the goals of the proposal. To my surprise, I have found some papers in completely unrelated topics credited to the research grant that funded it. It doesn't even seem like a serendipitous finding or semi-related tangent either, but rather a complete deviation from the grant's intended purpose.
I'm sure that there are other justifications for attributing research grants for publications as stated in this post, but it made me wonder...
How can one justify using grant money to fund research outside of your intended purpose of the grant? Is this a common practice? Are there any negative consequences to using your grant to fund extracurricular research activities? Under what circumstances is it valid to do so and when is it inappropriate to do so?