Every non-toy refactoring tool (and I guess a lot of other ones) needs to understand fixity declarations, imports, scopes etc. anyway, otherwise it would be next to useless.

 

"Sensible" is always a subjective notion, and tools should not have subjective behavior. :-) In other words: If it's legal, the tool must handle it. A lot of things which were initially considered nonsense/impractical/confusing are mainstream nowadays. Furthermore, there are a few experimental Prelude variants out there.