To answer your first question: teaching evaluations are supposedly anonymous. However, two experiences I've had are relevant:

• at some universities, including the university at which I am currently a graduate student, the students are invited to write comments by hand on the evaluation form. These comments are sometimes photocopied and distributed to the instructor along with a summary of the numerical evaluations. In a small class it's not impossible that the instructor would recognize the students' handwriting, and so I know who wrote comments about some of my courses. This is of course not an issue if evaluations are done online, which increasingly many institutions (including mine) do now.

• as an undergraduate I took a course that was being offered for the first time. This course was somewhat experimental in nature and so the professor in charge handed out a mid-semester course evaluation form. I wrote some comments in which I inadvertently gave enough information that it was possible for the professor to identify me. Since it was clear that I was frustrated with some aspects of the course he had me meet with him. (In the end this worked out well, as this professor wrote me a recommendation for graduate school.)