Is there any built in feature in SQL server that allows dual control updates, deletes and inserts?
What I mean by dual control is that it requires any two users to collude in order to alter the database. However, they'd be able run selects just fine.
Is there an inbuilt feature that allows this or will I have to roll my own?
Ah. No. And i do not think there is any other database doing that. 4+ eyes is an application layer feature.