I agree, it works. The companion has to fly all the way with the HON but not the HON all the way with the companion. I normally fly from DUS or LHR, pick up my spouse in TXL and we continue to Frankfurt. On the way back we do it the other way round. Fly together to LHR or DUS and unfortunatly I miss my last segment to TXL and she flies alone. Never had problems with that strategy.