With this feature you can decide whether or not the package will be counted as a registration when determining when a Fee Trigger applies. This setting appears under the "Settings" section of a package. Place a checkmark next to "Do not count this package against Fee Triggers".
For example, let's say you have 2 types of registrations: one for kids (Participant) and one for Bench Staff (see "Package Types"). Therefore, you would have a set of packages configured for bench staff and a set of packages for participants.
For the kids, you might have 2nd child discounts, 3rd child discounts, etc., which would be negative fees configured with the appropriate fee triggers. Suppose you have a user that registers someone as a bench staff and then a child as a participant. Because the participant registration would be the 2nd registration in their shopping cart, without use of this setting, the 2nd child discount would kick-in and be applied to the order.
In this scenario, you wouldn't want the child to get the 2nd child discount since they are really the 1st child (participant) in the cart, not the 2nd. The 1st registration is bench staff. The discount fee should only trigger on the 2nd "Participant" registration. To have this scenario work properly, you would configure all of your "Bench Staff" packages with this setting on.