How do US DOT rules apply to a Lufthansa flight origimating in German? The passenger will be checking his baggage onto a Lufthansa flight in Germany. Lufthansa is not subject to DOT rules on a flight not to/from US. IATA agreement may be the document you'll need to check with.

I still think an itiniery starts wherever you check in w/ bags. Hawaiian still collects baggage fees in Hawaii for UA code-share flights originating in islands from pax who flew to Hawaii on a single UA PNR. and it does not appear to be getting slapped by DOT. A round-trip to Hawaii may seem to be one itiniery, but HA treats the inbound and outbound as 2 seperate itinieries since you check in twice. As initiator of the inbound itiniery, UA bag rules prevail. On the outbound, HA is the first carrier and imposes its rules. BTW, UA now clearly states that HA will assess charges according to HA's rules now.

Edit: thought I was posting in thread about someone who was flying from US to Frankfurt, then flying (I think) Lufthansa onward. Just call me confused...