So in a trade call you talk to the other team. The other team's AGM, GM maybe President. In those conversations, you ask about medical history and I would wager Vaccine Hesitancy. Now that other team might lie and say that he will get it, or not, or that he already has, but that is a bad business practice as most F.Os do talk to other F.Os and if word gets around that you lie your ass off, most teams probably won't deal with you again.
Now there have been instances that Front Offices have lied and have done shady things re: trades. But I bet all of us here could name like 5 instances ever. In like ALL sports.
So I am sure that in this trade call, the Jays would have asked KC if he was really Vaccine Hesitant, and KC probably asked Whit if this was something that he would do - since he has another year left on his contract. And I am sure that the Jays got the right answer since they made the trade.
There have been multiple reports that the Jays were after a player but it didn't go far as they didn't want to get the vaccine.
But sure, in the fog of the trade deadline, this front office, which is known as too conservative, would throw caution to the wind and trade a real piece for a not-sure thing.
¯\_(ツ)_/¯