Like mail in rebates it creates a moral hazard on the vendor's part.

The right thing to do is to just discount the product and just re-use IPs unless otherwise reserved. Mail in rebates can be ignored or "lost in the mail" and seems to happen often enough for me to have lost trust in them. I have little control over what the vendor does, so I would rather avoid vendors who think screwing with me is ok.

I don't buy products with mail in rebates and now I won't buy into lightsail (Presume this thread is accurate and Amazon doesn't fix it).