Question about scripting of foreign keys

When I script FK_SalesOrderHeader_Address_BillToAddressID key from AdventureWorks.[Sales].[SalesOrderHeader] I get this:

ALTER TABLE [Sales].[SalesOrderHeader]  WITH CHECK ADD  CONSTRAINT [FK_SalesOrderHeader_Address_BillToAddressID] FOREIGN KEY([BillToAddressID])
REFERENCES [Person].[Address] ([AddressID])
GOALTER TABLE [Sales].[SalesOrderHeader] CHECK CONSTRAINT [FK_SalesOrderHeader_Address_BillToAddressID]
GO

EXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'Foreign key constraint referencing Address.AddressID.' , @level0type=N'SCHEMA',@level0name=N'Sales', @level1type=N'TABLE',@level1name=N'SalesOrderHeader', @level2type=N'CONSTRAINT',@level2name=N'FK_SalesOrderHeader_Address_BillToAddressID'
GO

What is second ALTER statement for (the one highlighted with bold font)? First ALTER statement already includes WITH CHECK, so isn't the second one redundant?