Deleted, then recreated users don't receive event notifications

Issue

When you create an event for someone, Google uses an internal ID to associate that event to them in addition to their email address. In the scenario where a user is:

1. created
2. invited to events
3. deleted
4. recreated

The events for which they were originally invited will no longer be tied to the recreated user account. Because the newly created user has a different Google identifier, they will not receive calendar notifications when the organizer modifies the original calendar event.

Resolution

Avoid deleting and recreating users. If accounts are recreated and the username had existing events, uninviting and re-inviting the newly re-created user will not correct the event. Duplicating or re-creating the event is required.