If you build your own package, and add a policy to a Package, there is a
Package Properties right click item on it.

One of the properties is Linkage. You can define it as Weight, Last,
First, Before a policy and After.

Well if you define it as After, but the policy referenced in After does
not exist, guess what happens to the policy?

It does not get linked in at all. That is probably a lousy failure

Just a heads up for anyone running into this.

I.e. You add a new package to a driver, and objects disappear that ought
not to disappear. Consider the Policy Linkage setting in the Package