[dentarg]

Note that Slack has only sent the email about account access since 2018:

>Additional security features: As of January 2018, we began sending an email every time your account is accessed from a new device; this is a simpler and more immediate way for you to be aware of new logins to your account than periodically reviewing your access logs.

(Quote from the "Slack password reset" email they recently sent out to affected users.)