There are now those players that don't want to proceed with the restart because of having no audience. Having supporters cheering for their team really is a big factor.
They are under on a contract, they will have to participate as that is part of their job, they will only be excuse if they have a valid reason.
If they will not participate they will break the contract and they will be sued which might affect their future in the NBA.
We are talking of huge money here as per their contract, especially the star players so it's a big lost for the players as NBA can always find a player that would play for a certain team.
I have watched a video on youtube saying that if the player will not be punished if they don't want to play this time. Yes it is part of their job as a player and they are under a contract but I think the health of every player is more important right now than the contract. Players didn't want this to happen and no one want too but if I'm on their situation, I will not risk my life too unless there are very strict guidelines that will be implemented but I'm not in a 100% condition still.