I want to to understand the context under which you would ask for it after the fact. Usually when you ask for leave, you tell the employer the situation you're in, and now you have all these extra sections under which you could get unpaid leave. Why would you ask for it after the fact? Is it just for documentation purposes?
Going back to my time in human resources, I would think once I've given you your leave, why would I need to confirm that I made the right decision to give you the leave to start with? If I did that, I'd be stuck with all these personal documents that I now need to protect under PIPEDA and other provincial acts that regulate other portions of my business. I would rather not even ask for this information.