Short Answer: Decide Fate, Dangerous Day Abilities and The Fool
Long Answer:
I am really loving the King mechanic in this game. The King is a character who looms over the entire game, shrouded in mystery for the most part as investigative classes cannot determine his alignment. He is a monument to scumreading - a character you must judge based SOLELY on his actions and speech. Most games he is untouched until the very end of the game as nobody is quite sure if he is on their side or not.
He also wields a ridiculous amount of power. Decide Fate is the main reason you might not want an important claim on trial, such as the Prince or Paladin. An Evil King would (and really should) immediately execute any Prince claim even if it means his death the following day. Sacrificing yourself to eliminate such a pivotal character in the game is surely worth it. I’d argue the only two roles you 100% Decide Fate execute on as an Evil King would be Prince or Paladin and maybe Sheriff if you don’t think they have knighted anybody yet.
Neutral Kings who have more faith in the evil roles might even consider executing powerful town roles if it is near the end of the game and they still have guards left.
There are 3 alignments for King, 1 of which will no doubt execute a Prince on sight and another that might consider it later. Consider it a 40% of your Prince/Paladin/maybe Sheriff getting executed when getting randomly voted to the stand.
Another threat to VFR are the multiple and dangerous day abilities that exist to inhibit speech or confuse players, like Chilling Touch or Distract. Even an assassin’s 10 second distract ability can create doubt in the minds of the town. Did that person just quickly type up a will, or were they truly distracted like they claim?
If a Reaper sees that somebody is being voted up for a role, they WILL cast Chilling Touch on them, causing them to be unable to claim and say anything at all. This person will likely get lynched or executed.
You could simply have your Prince execute them if you fear a Fool, but losing executes can be just as bad as not being able to vote for 2 days. Remember, Chilling Touch has TWO uses! Reaper can potentially get town to kill off 2 of their own just with their day ability. The counterplay to this is to allow the silent person off the stand and continue on with VFR on a second person as the Reaper cannot cast a day ability twice in a row.
The problem here is this - if this meta develops this way, evils can simply stay silent and feign a Chilling Touch and prevent town from getting their role that day. Entertain the thought and you’ll realize there are a lot of ways this meta branch can go, and hardly none of it is preferable for Blue Dragon.
Fool is a thing, and this version of Jester is so much worse for BD than Jester was for Town in ToS. Being unable to lynch for 2 whole days hurts only BD for the most part. Fools getting lynched is not an uncommon occurrence as roles in ToL are generally hard to prove. VFRing will literally come to a halt once the Fool is lynched.
I’ve been watching people try to VFR down the list 1-16 in this game and have watched it not be terribly effective. By all means VFR when it comes down to the final people or if somebody is acting particularly scummy, but if you randomly choose someone and they turn out to be the most important role of the game, you might consider choosing your trials more carefully.