There is no WARN act violation if the employee receives 60 days of severance and some consideration for vesting. Is there any evidence that didn’t happen?
Is the lawsuit itself not evidence? Do you think employees are sitting there thinking "let's waste money and time on a lawsuit that will have no impact." There must have been some good faith believe that Musk had no intention of providing severance. Is that really so hard to believe from the outside?
No, the lawsuit is not evidence. In the US, anyone can sue anyone for anything. That doesn't prove there is merit at all.
Until, and if, it's heard by a court, a lawsuit is just a one sided opinion.
There is really no point arguing over beliefs, it's easier to settle things with facts/data. "humans are logical and act rationally" has never been a good apriori.
The employees who lawyered up before seeing any official termination documentation are probably on the hook for any legal fees incurred so far. Now that it appears that an appropriate work suspension and notice of termination date (essentially severance) was granted, its likely that there wont be many offers from lawyers to act on contingency fees.