That can't possibly work correctly with runsv, given the way in which Unicorn performs configuration reloads. Eventually the original process that runsv forked will die, and runsv will try to restart it and fail (because the original process launched a new generation that continues to listen to the socket). Then 'sv stop' will fail to work because the new generation of master and workers isn't under runsv's supervision anymore.
nginx doesn't die. It just reloads the config file and applies the changes. I can't remember what Unicorn does because we almost never change its config.
