Omnirationality is the divine attribute in virtue of which when God does A, he does it for all the non-preempted reasons that in fact favor his doing A. (Here is an example of a reason preempted by a higher order reason: God promises me that as a punishment, he won't hear my prayers for the next hour; then that I ask God for something creates a preempted reason for him.) He does not choose only some of the relevant reasons and act on those, in the way a human being might.
One consequence of omnirationality is that when I pray for an event F, and F is good and in fact takes place, then I can safely conclude that F took place in part as a result of prayer. For a request is always a good reason to do something good, and while in principle the reason could be preempted, in fact it seems very unlikely that there was a preempting reason in this case. At this same time, in this case we cannot say that the good took place entirely as a result of prayer, because the very fact that it was a good was also, presumably, a non-preempted reason for God to bring it about.
Here is another example. Suppose Job leads a virtuous life in such a way that there is good reason for Job to have good things bestowed on him as a reward for the virtuous life. And suppose that, in fact, good things befall Job. Then we can confidently say that they befell Job in part in order to reward Job. For by hypothesis, God has a reason (not a conclusive one, as we learn from the Book of Job!) to bless Job, and the reason seems unlikely to be preempted, so when he blesses Job, he does so in part because it rewards Job.
The flip side of this is that, by omnirationality, if a sinner who has not been forgiven for a sin has a bad thing happen to her whose magnitude is not disproportionate to the sin, that bad thing happens to her at least in part as a divine punishment, unless some sort of preemption applies, since God has a reason to punish.
Forgiveness, of course, would preempt. But I assumed here the sin was unforgiven. Maybe one could claim that the redemptive events of the New Testament changed everything, preempting all of God's reasons to punish, but that does not seem to be the message of the New Testament. It really does seem that God's reasons to punish unforgiven sin are not preempted even in New Testament times. This does not, of course, mean that all evils that happen to people are best seen as divine punishments. First of all, forgiveness of a sin preempts, and probably annuls, the reasons of justice. Second, even when the justice of the matter is a non-preempted reason for God to allow the evil to befall, it need not be the most important one. God's desire to use the evil to reform the sinner or to glorify himself in a deeper way, may be a more important reason, sometimes to the point where it would be misleading, and maybe even false, to say that the evil befell because the person sinned—we could only say that the evil befell in small part because the person sinned.
Finally, as Jesus himself warns, that an evil befalls A and does not befall B does not imply that A was more worthy of the evil than B. For God may have had many additional reasons for allowing the evil to befall A and keeping it from B besides the merits of the wo.
We can try to probe more deeply by asking counterfactual questions: Would God still have had the evil befall A had A not sinned? But I think such counterfactual questions tend not to have answers.