This is triggered when the user account is deleted, not if they can't login/are suspended, for which the usual account recovery mechanisms apply.
By far the most common scenario for this to happen is that Bob leaves Corp, and Corp intentionally deletes his account. If Corp has set up billing sensibly, the project will have a central billing account whose admin will be notified, but if Bob signed up on his personal credit card, there is nobody to contact here either.
Look, if I a company owns BAR.COM and they delete FOO@BAR.COM they could recreate that account. Any other service in the world tied to that address will be recovered, except Google's own service.
You have knowledge the account belongs to BAR.COM company, why not contact them? How about a warning to the person deleting the account, telling them that a particular GC service is dependent on it? You know exactly what you plan to delete, after all. How about requiring at least two emails on the GC account so that there is an escape hatch? Can you think of any other ways of preventing this disaster?
Yeah, I get it, the user should have avoided that mistake. People make mistakes, it's the fact of life. You have built a minefield for your customers and left them to sort through the carnage of the explosion.
By far the most common scenario for this to happen is that Bob leaves Corp, and Corp intentionally deletes his account. If Corp has set up billing sensibly, the project will have a central billing account whose admin will be notified, but if Bob signed up on his personal credit card, there is nobody to contact here either.