"Replace Action" should make it less easy to create a zero-user action

The Action Editor's "Action > Replace Action" and "Action > Replace with New Action" seem inherently and unnecessarily dangerous. By design, they (usually) remove all users of the current action in favor of, respectively, an existing or newly duplicated action, leaving the old action with no users.

While the user may occasionally intend to throw the old action away, most commonly these operations are used to switch multiple objects between a set of saved actions. and it's easy for the user of these operations to miss the fact that the old action has been left with zero users, increasing the likelihood it will be lost.

I think these operations ought to include some sort of "Add Fake User" checkbox that defaults to checked and creates a fake user for the old action whenever the operation results in all users being removed.