When entering a gift you should be given a warning if you try to use a Package that has a date set in the future(so isn't currently valid).

Currently when entering a package relating to a specific Appeal, ALL associated packages are displayed in the drop down menu, this means the wrong package can easily be selected. We use EARLY Bird offers for event registrations and therefore have a range of packages set up at the start of each year to cover the full range of gifts anticipated.

(Setting a start and end date for the package doesn't appear to  'Lock out' the package being displayed when entering a gift. The only way is to make it Inactive which is not ideal as means you have to go back at a later date and make it active)