Laguna is not up to MotoGP standards despite all the changes done to improve safety this year, but it's not that bad, as long as there aren't any freaky accidents (like tires exploding or engines blowing and leaving oil on the track).
The MSMA (association of manufacturers) and DORNA (owner of MotoGP rights) are very interested in the US market, they wont allow the riders to boicott the race.
This has happened sometimes in the past but it's not likely tomorrow, in the past the circuits were extremely dangerous compared to Laguna Seca, and there were no big sponsors ready to sue the riders if they didn't to race.
So let's just enjoy the race and hope there are no nasty crashes.