Comment by simiones
> Basically if Sally, the CTO of DankStartup, signed up for Taskrabbit or whatnot, it's possible for you as the owner of the domain to impersonate Sally in the context of that relationship.
I don't think this is the issue, unless someone went to some pretty extreme lengths. Configuring OAuth such that the company Google Workspaces account is recognized by Taskrabbit as a valid SSO option is not as simple as signing up to Taskrabbit with your company email instead of personal email.
Even then (in my experience) it's pretty common to setup an email based account and it will auto link to an oauth one that already exists. Even if Google revoked oauth, many platforms let you use the email directly to login