It is very acceptable to me.. There could be 2 "Bob Smith" in "Montreal"..
My decision was to not interfere with this. I thought, from reading the assignment, that there were no requirement asking for any restriction on this, so following that logic, I thought it would actually be wrong to do so.
But I've read others used some fields as the key as well. It's really of matter of making your own choice.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com