You can't just look at the likelihood of occurrence, you also have to look at the severity of the consequences of the occurrence.
Risk is usually defined as consequence x likelihood. If you want to keep it simple (which seems a good idea for this thread) suppose there are three levels of likelihood (low, medium, high) and three levels of consequences (low = annoyance, medium = have to deal with it but it is not life threatening, and high = life-threatening). So, I suspect we would all agree that the likelihood of running out of air is low, but the consequences are high. So the risk involved with running out of air is not negligible, even if the likelihood of it is low. So we train for it and equip for it, to try and mitigate the consequence and thus lower the risk.
What's not said in your post is that you seem to be concerned about the
joint likelihood of running out of air
and either (a) Covid-19 is involved in either the donor or receipient, or (b) whether the consequences of having been forced to just change your standard equipment configuration causes you to respond less well to an OOG incident. Some posters in this thread are in the (a) category, some are in the (b). In the (a) category the concern is lowered likelihood of
both OOG and Covid-19 happening, but since the consequences are still high (even higher, perhaps) it doesn't change the risk assessment. In the (b) category, we are perhaps less able to mitigate the consequence so the risk is higher.
Either way, the
precautionary principle has been applied by Buddy Dive, which makes good sense until more is known.