I noticed SAS charges relatively cheap prices for extra pieces of baggage - for instance 650 SEK for 1x23kg to long haul destinations ("Övriga världen").
What happens if I only fly the first leg with SAS and the rest (and the longest distance with someone else)? Qatar Airways or Ethiad charge a hefty price per KG, so 23KG extra would cost between 300 and 600 USD. It would be much cheaper to stick a SAS leg first and pay SAS baggage fees - for instance CPH-ARN-XXX instead of taking the direct route. Does this work?
Edit: Oops, I didn't check who interlines with SAS but I believe at least QR does.