If you disable the deduplication check you may get context issues when creating new people under to company context.
For example go to 3G Homes and create a new Person. Now navigate to A Midland & Sons and create another new Person.
Note that the top content displays 3G Homes rather than A Midland & Sons as it should.
Context is incorrect when deduplication is disabled and you are creating a Person under the Company context.
This is a known issue and has been escalated to development. It will be resolved in a future patch of Sage CRM.
This issue will not occur if deduplication is enabled.