As an option, when setting up a subscription, you can specify that SQL Server will not synchronize the published articles with the destination tables. SQL Server assumes that they are already synchronized, and inserts, updates, deletes, or modifications to the published data are replicated to each subscriber as soon as the subscription are established.
In this case, it is the responsibility of the user setting up replication to ensure that the table schema and data are identical for the published article and the destination table. The advantage of this option is that it allows changes to replicated data to be immediately distributed to subscribers, without incurring the system overhead associated with synchronization. It is intended for advanced users who will be implementing a custom replication solution.