“voluntary”
You don’t think note will be made of who doesn’t attend?
...and one best not be the first to quit clapping...
At a former company, HR sent out "anonymous" surveys - some questions like those mentioned above, plenty more of "tell us how wonderful the company is, and please be specific" ones as well.
I tossed it in the trash. A couple of weeks later, HR came to me and asked why they'd not received my anonymous survey, yet.
Think about it.