What are the potential ramifications of a student intentionally deanonymizing his/her class evaluation? Presumably, evaluations are anonymized to protect the students from possible retaliation by the instructor or institution. 

Is there anything in the reverse direction (keeping that information hidden is beneficial to the instructor)?

What are potential consequences if a student chooses to place identifying information (e.g. knowledge of a particular conversation) onto an evaluation?



The exact situation is that one of my friends was considering discussing a very long conversation she'd had with the professor on the class evaluation, and how it exemplified issues she'd had with the class. She's taking a class with that professor next semester, which is a big issue for the student. That issue aside, I'm wondering if there would be good reaons to avoid this even if she would never take another class with this instructor.
The only ramnifications I can think of is that whoever handles, edits or publishes that class evaluation may recognise the deanonymisation, consider it accidental and thus decides not to pass it for that reason.

As you can always pass deanonymised criticism to an instructor, be it by mail or by putting it on public display, there seems little point to me to protect the instructor from it on this particular medium.

Something else you might consider though is that even if the professor does not want to retaliate that criticism, they will have more difficulties to fairly evaluate the critic, which may have effects in either direction. While this is some annoyance you could spare the professor, it would also happen with non-anonymous critique made in other ways.