When I look at some of the Salesforce built-in objects, I notice some lookup field do not have a child relationship name defined - and I cannot set them myself.
For example if I look at the "Campaign Owner" field in the "Campaign" object (via the UI), there is no "Child Relationship Name" displayed (see screenshot). If I edit the field, I cannot manually set a child relationship name.
I am trying to understand whether I can rely on always having a child relationship name - and it seems I cannot. I'd like to understand, then, under what conditions is it not possible to have a child relationship name. Is that specific to Owner fields ? Is there another reason ?