As for the point you bring up, perhaps it could affect the mindset of the competitor, but if it does that is tough luck. There will always be more opportunities for them to get over it, bring it back and perform to their top potential again. Personally, I can really not genuinely see this sort of thing throwing someone off so much that they break down entirely, quit cubing, and never compete again (NOTE: exaggerated case). And if someone did react such a way, to be honest I don't really think I'd be disappointed to see them leave.
But even if we do make a mountain out of a molehill in this situation, I still think my argument is too strong, i.e. this would be such a rare occurrence and could never be repeated with the same competitor, therefore it doesn't justify a blanket +2 rule for every other case where it is the competitors fault. It's a matter of balance, and the balance is significantly against this very rare occurrence.
And I don't think it's a fair statement to make that the person is likely to miss out on a chance at an average because of the DNF. For the average they are currently in they still have four other opportunities to solve the cube and get an average. Alternatively, if there is a chance that the DNF is so costly to their average in terms of raw times that they miss out on the next round, to be fair they probably didn't deserve to get to the next round anyway. I justify this statement by making these points:
- A person gets five solves in an average, so it is not fair to pinpoint the blame on one of those solves. To put this another way: each solve in an average only comprises a 20% contribution to that average (and that includes the best and worst solves which are eliminated; they still play their part).
- If the competitor's times are so borderline to the cutoff needed to get to the next round then you can hardly say they were genuinely disadvantaged by that one solve, as their times can't have generally been good enough regardless.
- If a competitor has a solve that has 2 seconds added to it, and that solve is still not the worst solve in their average, and therefore contributes positively to their average, I believe we are left with four possible situations (not exclusive in all cases). In my opinion, in none of these situations is that one solve which hypothetically receives a DNF so devastating that it is solely to blame, or even largely to blame, for the competitor missing out on the next round. I will illustrate these situations with slightly exaggerated examples to make the points clearer:
If a solve with a +2 is still counting then either:
1) The solve itself was probably not reflective of the competitors real times, e.g. (15.00), (16.50), 15.50, 15.50, 13.01+2=15.01
2) They had another solve which was very poor, e.g. (15.00), (20.00), 15.50, 15.50, 15.50+2=17.50
3) There would have been little difference between their worst times anyway, e.g. (15.00), (17.51), 15.50, 15.50, 15.50+2=17.50
4) The competitor has generally inconsistent times, e.g. (13.00), (20.00), 15.00, 18.00, 14.50+2=16.50
Now let us consider these situations in regards to the potential to ruin the average if those +2's had instead been DNFs.
In situation 4 it is impossible to say the competitor deserved to get to the next round, given their times are all over the place, and seemingly in any given situation could pull out an average anywhere between 13 and 20. Even though changing the +2 to a DNF would negatively impact their average, the negative impact is a result of their general inconsistency, and not because of that one solve which is only contributing 20%.
Situation 3 can be dismissed outright; if the +2 had instead been given a DNF it would not affect their average very much at all.
Situation 2 would definitely affect their average, but at the same time the competitor has had four other attempts, and like situation 4, their lack of consistency is the main reason for their receiving a poor average.
In situation 1 we have to assume that the competitor has generally consistent times (otherwise refer situation 2 or 4). If their times are generally consistent, then although their average is negatively impacted, it would still be reflective of their abilities. If they miss out on the next round with an average that is still reflective of their abilities it would be a stretch to say that they genuinely deserved to get to the next round. It would certainly be false to say that a DNF for that one solve was the reason they missed out on the next round.
To conclude this long point: The DNF in any of the cases cannot reasonably be said to be the reason the competitor missed out on an average. At most one could only claim it contributed to several reasons that, when combined, become the cause of the competitor missing out on the average.
At the beginning of this response to your point I italicised the phrase "in terms of raw times". If you were wondering exactly what I meant by that, hopefully it is now clearer: I don't genuinely think that the DNF is ever that costly to an average, as it could only be a contributing factor to a range of causes. It is only if you ignore all of the factors and look at the raw times in themselves does it appear as if a DNF is so costly (in some cases).
And of course this is not the only reason I suggest the removal of the +2, but other people are arguing other points. I don't see any need to join in to a large extent, unless I see somewhere I feel I can contribute. Again, refer to my giant post above to see some of the other arguments that have been put forward.