What's the risk of being wrong:

I live in an apartment building with a fairly sizable percentage of residents (maybe one in four) who don't wear masks in elevators and public areas... which raises a question in my mind regarding the risks of being wrong. 

Our species is dealing with a novel virus about which the scientific community continues in its efforts to understand. The most accurate statement any of us can make on the question of masks relative to their efficacy in reducing risk of contracting and spreading the virus is that none of us can be certain of the extent to which the mask offers protection to oneself or others.

But, if we approach this in the most clear-headed way possible, we can deduce the greater risk in being wrong on the matter given what the empirical evidence may reveal at some point in the future.

Once the evidence is in, we will know that either the masks are (a) no (or negligible) measurable protection (for anyone) from the virus or (b) the masks offer some measurable protection from the virus.

One might argue that every time someone not wearing a mask rides an elevator with someone who is wearing a mask, one of those two people is wrong—but the potential for harm in being wrong is disproportionate to the non-mask-wearer. If they are wrong, they have contributed to the virus' spread; if the mask-wearer is wrong, they've been inconvenienced and uncomfortable... and maybe even a bit embarrassed once more is known about the pandemic.

I'm referencing the virus, but this could apply to any number of topics in which there is an incomplete understanding of the situation (i.e. most situations in life).

What's the risk of being wrong? A functional society in which members of the species cooperate to ensure its survival gives the question humble consideration... or it may cease to exist.