Together with a colleague from a different university, I wrote a paper that has passed peer review in a respectable journal and is currently in press. The topic of the paper is very far removed from our usual research areas; let's say that my colleague is a chemist but the paper is about history (all details changed). We collaborated and wrote the paper in our spare time.
Now my colleague spoke to some university administrators and was told not to use university's affiliation on any papers that are written in the spare time / are outside of his or her direct responsibilities. As a result, my colleague wants to remove their affiliation from the paper.
I should add that my colleague is a senior researcher employed by the university, and that it is quite a well-known university in Western Europe.
My question is: How weird is that? Is such a policy common?
I was under impression that universities are only happy when their affiliation is used, and unhappy if it is not used.