One would think the fact that cases in the US are rising faster than they ever have would be deterrent enough.
But people feel intense pressure to follow the norm. In the absence of clear messaging from some third-party authority, that norm is generally “what we’ve always done.”
Messaging like this can change the perceived norm to “it’s okay to stay home this year.”
With the pandemic I completely stopped following the details of the aviation and airline industries (a combo of not flying and impact to my family working there.) In normal times, many tickets would be changeable with a hefty change fee. Has the industry switched to even more restrictive "use it or lose it" fares?
Pretty much every airline is offering credits for future travel, at the very least. I doubt too many people are in this position.
At least when the lockdown first kicked in during the spring, my impression is that most airlines let you cancel your tickets for a full-price credit that you could use later. That's what happened when I cancelled my "non-refundable" spring break tickets.
I got an email from Alaska Airlines recently saying essentially the same thing. They'd rather let people cancel in return for a credit than have people simply not book at all out of fear of needing to cancel. Hell, they'd be happy to take your money now for a plane ticket in the future. It's basically a loan to help them weather the pandemic.
Messaging is important. It irritates me to no end that newscasters aren't wearing masks--for example. There are a lot of people who are "Oh, the lady on TV is wearing a mask--so I guess it's bad enough that I should, too."