Hey @...,

James here from the Product Team. You ask a good question, so I thought I'd reply with an offical comment.

The reason we allow duplicate domains across orgs is to support our multi-orgs feature, and to cater for the situation where there are multiple relationships with a customer - such as with different departments, brands of holding company, stores, regions and locations - and they all share the same domain.

We've recently been evaluating enforcing uniqueness of org domains if the multi-org setting is turned off, but in doing so, it can create data integrity issues that cannot be easily resolved if multi-orgs is turned on, duplicate domains are created, and then multi-orgs is turned off. As a result, we not yet committed to doing that.

I hope this helps clarify some of the background and thinking behind this setting.

Thanks
James