That's what I immediately thought when I first read it, especially now that Github Pages are served over Fastly's CDN [1]. Then I realized that Github Pages do not support server side (301) redirects at all. Quite a big turn-off when you move an existing website over a new platform.

[1] https://news.ycombinator.com/item?id=7019148, https://news.ycombinator.com/item?id=6975830