That's a reasonable approach, but due to the synchronous requirement I guess the offload factor would be minimal. When I want to download something I might as well enable wifi and see if it's available locally. After I'm done there's really no incentive for me to keep seeding or even have wifi turned on.
> P2P networks like Bittorrent pride themselves on being available despite high churn, so this is right up their alley.
This really isn't applicable to opportunistic mobile use of IPFS, as you are unlikely to have a large enough local swarm to guarantee uptime or availability.