I was wondering if there is a global setting for subscription-manager you can use to change the behaviour that enables custom repositories by default.

I know it is possible to change Product Content defaults on activation key basis but this only affects repos that currently exist in Satellite, it doesn´t affect repos that I add after the activation key has been created.

This means that as soon as I add another repo to a custom product and publishes the content view, the repo will be enabled on ALL existing hosts that are using the content view.