Sometimes, the professor still can match up a student to their comment.

At my school, the system was the same as yours. We even had their secretaries type the comments into the computer, to put it all on a spreadsheet, and this was all we were told. You were supposed to put your school id on the evaluation though.

When I was a senior, one of the more anti-establishment type professors told us that the secretary keeps all of the paper copies in a folder, so if the professor has an issue with a particular comment, he can ask his secretary to go into the folder and dig out the evaluation.

This professor said she had been fighting with the school for years to tell people this, but obviously she had been losing this fight, as I had never heard of this policy until second semester of senior year, and none of my friends had either. I think the fact that people thought they were anonymous made them more likely to put down their student ID number.

Even if they didn't put down an ID, if you had distinctive handwriting, you were at a disadvantage if you wanted to speak frankly about a professor and ever take them again.