This is what the current SWEFTA rule says:
It is compulsory to hand in scorecards, regardless of whether the full course of fire has been completed or not. The only exceptions to this are if for medical reasons, the competitor is no longer able to continue; or if it is not longer possible for a competitorís rifle to be discharged due to mechanical breakdown. Shooters not handing in their cards will be credited with 1 hit.
We chose to use the 1 hit system so as to distinguish between "penalties" and "no-shows". If the person got a zero, some time later it might be hard to recall if they just weren't there, or tore their card up.