I didn't think of that. I didn't really have a reason for asking the question. Mostly I think when I was reading it, it just struck me as convenient that there relationship be established and started in that manner.

But that's also a really dumb thought because, yeah, of course you establish relationships between major characters like that. ::eyeroll:: And, you're right, same reason to send Hagrid to explain it all to Harry. It introduces an important character and establishes an important relationship in those characters' lives.