My company in Seattle is still voluntary to go to the office, but you must sign an attestation that you are fully vaccinated before you are able to participate in person in any company event. You are also not allowed to travel without signing the attestation and you will be accommodated for not getting vaccinated in the short term by the teams having zoom links for you to join remotely. Oh, and if you signed, you can't expense anything you do with a fellow employee who hasn't signed. This policy will be revisited in September.
They did it for 2 reasons, #1, liability, they don't want it, and #2, some people have been going into the office for awhile and they want to be able to be with their fellow vaccinated employees without a mask. So they are finally going to get that.
It had other unintended consequences, it's brought the company kooks out of the woodwork, so now I know which morons I need to avoid. It also got one of my colleagues to finally get off his ass and get a vaccine scheduled. I'm ok with both of those outcomes.