Would you ask somebody who had you in an A/B test to destroy the feature?

Surely A/B does not require PII? In FB case-if the model's purpose is to identify individuals then yes, it should be undone as requested.

no.

i would argue it’s not even your data, but that’s for another time.

It's yours at least to some extent under GDPR.

I am going to guess no.

Why would it matter, models are regenerated frequently, from millions, billions of other data.