The European way? Announce it months in advance (which is when it was decided anyway) that you are in the process of layoffs and align with both investors and employees about the plan.

Well in the US if you have more than 200 employees, you do have provide 90 days notice / severance for mass layoffs under the WARN act so.....

That is if you call them layoffs.

A big co announced to its employees 2 weeks before their assessment that the percentage of employees that will need “improvement” increased from 3% to 10%, and that this year they will offer in lieu payments for those who do not want to do the “improvement program”.

So there you go, 10% with 2 weeks notice.

Your wording is very odd, but if I understand correctly the company announced it would be putting 10% of employee's on an improvement plan, with your belief the goal being termination, and they offered buy out options of employees would voluntary separate?

If so, then that is not a layoff, and it often a common practice to avoid layoff, people already on the fence, close to retirement, etc will take the buyout.

I fail see what the issue is here....

That sounds like 2 weeks PIPing notice, but how long were they on PIP before being terminated?

Virtually everyone got the in lieu payment after being discouraged by the direct management to pursue the improvement. They immediately left.

The improvement was a two month program.

Yes, actually. I find silence (or evasives) to be better than outright lies. It gives space to read between the lines.

not really because you will get the same response even if there arent any layoffs for real.