Correct me if I'm wrong. IIRC, there isn't a status code for temporary moved *with a timeout. If you use 307, it means the browser will always still check the original apple.com first, then get redirected to apple.com/live. Using 301 would make browser go to apple.com/live directly which improves response time. When the event is finished, they can do a 301 on apple.com/live back to apple.com to overwrite the rule.
Or lazy about their redirecting. 301's are supported by pretty much every browser, indexer and wget/curl whereas 302's sometimes fail on those. Its also pretty easy to reissue another 301 from /live to com/
I'm fairly certain they just want you to land on the live page, even if you can't view it in the current browser. It's about eyes on page to spur you to either stay tuned or move to a browser that works with it.
