The "soft credit this individual" check box on the spouse relationship tab is hard coded so if you click it for one spouse, it automatically clicks for the other spouse as well. That means any gifts made by either spouse are automatically soft credited to the other spouse. This greatly increases the risk of sending two mailings, and results in gifts being double counted in some reports.  It should be possible to decide if we want to soft credit both ways, or if we only want to soft credit in one direction.