I'm not Michael, but I think I can answer that. Moving to CA for the 3-months of YCombinator has traditionally been non-negotiable. After the 3 months is up, you can move wherever you like, and many do.

The only exception to this I'm aware of is that, in light of recent US immigration policy, YC is optionally holding interviews for S17 international founders in Vancouver, and is reportedly planning to "experiment with allowing founders who can't get visas for the duration of our 3-month program to participate remotely." https://blog.ycombinator.com/us-visas/