I think it should be possible to "cover" for a teammate in some manner.
Good point, certainly if we had all 5 man teams as FireBender suggested then we could do this and a single non-submittal wouldn't hurt. But then the flip side is that a non-submittal should hurt some because it's not a good thing to do. The key is to make it hurt some but not too much as well as make sure that if 4 man teams feel the pain then so should 5 man teams.
We have eliminated the explicit -2 point penalty and we've moved team bonus calculations to averages so the non-submittal wiil have no effect there. The only thing left is the impact this has on base score and my solution does make it hurt some and also makes it hurt *relatively* fairly between 4 and 5 man teams. Yes, as you point out the 5 man team has a 20% higher chance of this happening and that is *somewhat* unfair to the 5 man team but the other way around makes the 4 man team bear all the burden of this and the 5 man team none of the burden. My solution isn't perfect but it's closer to fair than not.
Your suggestion of a 2nd "backup" game that could be used in a limited way deserves some consideration. I think it's very likey that the team may have such a backup. In general quite a few folks have a couple of games to select from. Allowing someone to use such a game to lessen but not eliminate the loss from this has merit. I would suggest that the concept of having a backup is what is different between a 4 and a 5 man team. A 5 man team automatically has a "backup" game, in this case from their 5th player. I would say this is a good solution. I think you might want to allow this for 4 man teams and let 5 man teams behave as they have already. That's as close to fair as one could reasonably expect.
The downside of this solution is that it does require some extra rules and exceptions to rules and I think it therefore fails the test of Occam's Razor. In any case I am not quite so adverse to rules and exceptions to rules as it seems many here are and I think this is a less harsh and in fact preferable solution to the one I proposed. My proposal may be simpler but it's also harsher.
I think each solution is relatively fair and I could live with either. But I do have difficulty with allowing a condition to exist that would always penalize 4 man teams and never penalize 5 man teams. I can accept luck, I just can't accept bias.
Tbh, this does not seem like something that HAS to be in stone before round 3 is released as its a contingency end of round issue.
Not quite so sure about that, certainly we could start the round and decide early in the round, however we have precedent that says we don't change rules in the middle of a round. If this situation comes up at the end of this round it's far better to have decided before the fact instead of after. As to the probability of it occuring, it occured this round and so I don't think its too unreasonable to assume that it might occur next round as well.