As we know airlines combat hidden city ticketing by cancelling your entire ticket (including return trip) if you skip a leg. But how is this handled -- what happens if you are late from your connection, can this misfire? I guess the question is, do you need to worry that a late connection causes your entire ticket to be forfeit? Especially because the delay easily can be a day or at worst even more in case of transoceanic routes which only fly once a day.
It would be very rare and unusual for the airline to void the rest of your ticket on purpose in case of a delay with a "hidden city" argument . They only would do this if they assume you missed the connection on purpose.
However, when a missed connection occurs, some rebooking needs to happen and it happens depressingly often that your return flight get wiped out by accident or incompetence, especially if multiple different airlines are involved (marketing carrier, multiple operating carriers).
I guess the question is, do you need to worry that a late connection causes your entire ticket to be forfeit?
Yes, you do. But not because of hidden city ticketing penalty but because of complexities and incompetence in changing, rebooking, or re-issuing the existing ticket. Best practice is to check the confirmation number online with the airline after the change and to check in as early as possible. If they screw up you are still entitled to transport but it can take a lot of time and energy to sort this out.
Example: we were flying outbound with Delta+KLM but due to a delay we got rerouted with Air France. My return on Al Italia was wiped out. My son+partner returns were perfectly fine although all 3 tickets were on the same reservation.