This is a really fun, clever idea for a weekend project. I'd be very curious to hear what your experiences are in a month or so, or after some future rejection email, to see whether it really conditions you.
It might be interesting to send the email at random times on random days so you can't get used to it, which I believe is a similar method to how games will increase your response to rewards by making them irregularly timed.
Either way, nice job!