If we look around at any train show, we will see that the majority of those attending are of "a certain age" and are probably no more likely than a young person to CATCH the disease, but are especially prone to a serious even deadly result if they do. Also- many of those who exhibit are probably not "young" either.
Imagine exposing these to hundreds, in a closed hall? And how many HANDS touch and pickup the trains on display? If we look at the practices that are in place to "safely" run a public business- wiping everything down, sealed packaging, building ventilation, and social distancing - we see the wisdom of this decision more clearly. Should those displaying trains have to wipe them off w/ alcohol after every touch? All these would be the recommended things to do. And what about the financial losses to the Eastern Division TCA if they "social distance" all those "private" dealer tables, cutting down the exhibitor fees by 50-66%? And operating at a 50% reduction in attendance??
And for the hobby- imagine the headline: "Hundreds of senior citizens contract Covid 19 at a York model train show". It would look and be very dumb to do.
Maybe- in the middle of the summer, outside in a huge field somewhere like the Carlisle Fairgrounds, where the Corvette and other shows are held?? Carslisle Events held shows all last summer and as far as I have seen there were no major issues.
Here is where you can go to see their protocols for Covid:
https://carlisleevents.com/covid19