It is not unusual for computer science research to involve observations of human subjects. If your research involves human subjects, you should consult the Conjoint Faculties Research Ethics Board (CFREB) pages for information on how to apply for approval for your project. If you are in doubt about whether or not an application is necessary, the CFREB is receptive to requests for guidance.
As of 30 April 2010, the Department of Computer Science no longer has an ethics blanket approval for "system usability surveys". Students and faculty experiencing problems with ethics approval with their work are encouraged to talk to the CFREB, the Associate Head - Research and Planning (firstname.lastname@example.org), or the Head of the Department of Computer Science.