copecopecope

That hasn't been my experience. RSUs are taxed at vesting in the US.

I hear where you're coming from, but from my experience, the canary phase usually lasts less than an hour. And the traffic is usually split randomly, so the same 2% of users aren't at elevated risk for every deployment. I don't know how Slack does it, though.

At some point a new build needs to roll out to production. There's always going to be some risk that something goes wrong, so better to test with 2% of the population initially rather than 100%. By then, the build has already gone through integration tests/dog-fooding, so if something goes wrong in the canary phase, it's generally due to some production environment configuration issue.

But this is an antibody test, for people who have already recovered from the virus. False positives in this case are precisely what would give people a false sense of security.