Hi,
Tried to find a proper forum for this question regarding a huge fare difference for a Scandinavian Airlines flight (probably fits for other airlines as well).

Was looking for fares from Spanish south coast to Stockholm a few days ago. The direct flight from Alicante to Stockholm was very expensive. Looking at flights from Alicante to Copenhagen however were cheaper, including one transfer flight where the expensive flight to Stockholm was included.

I have heard rumors that you will get fined by the airline if deciding to travel only one part of the entire leg of a one-way flight. It's not that they can force me to get on that flight, like, I might have gotten frightened as hell by something, fainted, been delayed and decided it best to find another way to travel, IDK.

Just trying to clear this out since a friend told me I might get a fine from the airline if doing something like that.

The practice to which you you are referring is called hidden city ticketing or "skip-lagging".

Obviously any checked-in luggage would go to the final destination; and if this were done on the outbound portion of a round-trip ticket, the return flights would be canceled.

A traveller who made a regular practice of this could face consequences including closure of frequent flyer account and bills for the higher fare. Repetition of such behavior is evidence of intent to violate the rules.

However, for a very rare (as a percentage of total flights with that airline) or first-time event, no, nothing is likely to happen. As you note, the airline has no knowledge of the reason you would fail to board your connecting flight.

The other risk is that, if anything happens to the flight to Stockholm, the airline thinks you want to be in Copenhagen, that's where they're contractually obligated to take you, and that's where they'll reroute you to. Getting from Copenhagen to Stockholm is on you. Granted, this doesn't happen often - but it has happened, and it will happen again. Just have a Plan B ready to whip out in case it does.

Yes, this happened to us once. We booked MMX-ARN-CPH-HKG return to get a cheaper fare (we lived on the Swedish side so either airport would do). Anyway, the return flight went MX and I asked SK if it was possible to book us to CPH instead of MMX (they are 30 minutes apart by car). SK said no, and we eventually did HKG-FRA-ARN-MMX. Once again, no issues with us since MMX was 20 minutes from our home.