A business customer ends the relationship and sales deletes her in the CRM. What happens to her IdP user in this model, what is the consequence, and what is the design trade-off?

Question

Accepted Answer

The deletion is propagated and the IdP user is deleted completely, with name, password, e-mail and company; if she later wants to shop as a private customer, she has to register again.
The delete flow is short: delete the Customer in the CRM, search the user in the IdP, delete the user completely.
Why choose full deletion? It is simple, leaves no half-populated user behind and serves data minimisation: once the business relationship ends, there is no reason to keep her data, and deletion obligations are met in one step.
What does it cost? The IdP user may not have been created by sales at all. If Anna registered privately first and the company was only added later, deleting the business customer destroys her private account too, including her own password and her consent. That is why the model states the consequence explicitly (a new registration is required) and why it insists that account and password LCPs be aligned with it.
The alternative would be to delete only what the business-customer LCP owns, the company attribute, and leave a self-registered user in place. That requires knowing where the user came from (CRM or self-service) and checking that a valid consent still covers the remaining data. Neither option is wrong; what is wrong is not deciding, because then each LCP silently assumes a different answer.
Go deeper:

Art. 17 GDPR: Right to erasure — when personal data must be deleted, for example once it is no longer needed.