This has been puzzling me all day. I've just sold off a Pentax lens (for less than it was worth, really) and the guy who bought it decided at the last minute that he wants a receipt for it, which I am going to have to post to him. We did face to face and he had not mentioned anything about wanting one prior to handing the money over and having the lens, which he inspected thoroughly before paying. I've now become a bit annoyed at this new thing, and although he said its just in case, I cant think.. just in case of what?
Is it a reasonable request? Its not one I have faced before, and I dont have anything resembling a receipt book in my possession, nor a printer to print one out. Would it be unreasonable of me to now refuse to give it?
Call me puzzled.