We have never had someone ask that. I think your concern is reasonable. When people do renovations/alterations in my building, the managing agent looks over a packet and if necessary, submits it to our building engineer. This does not sound like a full-scale alteration, but I would either flat-out deny the request, or maybe tell her that she has to provide pictures of the unit and get the specs on the specific unit and your building engineer will have to review. Also, it sounds to me that the vent will have to somehow be attached to the window frame--that means they may have to put holes in it. Do you want to let them do that? Are your windows under any sort of warranty?--If so and holes are put in the frames, that might void the warranty.
I wouldn't deny the application based simply on this request, but I would make it clear that approval of the applicant is separate from approving the installation. If you normally issue written approvals, just to make things clear, you may want to add a line to the effect that approval is of the applicant only, and is not a grant of permission for any alteration/renovation work or installation of any appliances/equipment that may have been discussed at the interview.
