a couple things:

the extra $600 the government gives for unemployment won't last forever. pretty soon, the union workers will need to go back

also if the workers don't want to go back, the majority of them will be in luck as when the casinos reopen, they'll be doing so on a bare minimum staff until the customers fully return.

the bulk of these workers may be laid off for the rest of the year at a minimum.

it's not going to be a choice for them.