As Ashley said, it can be helpful to make MP's of entire families for several generations -- because then if there is a merge (whether correct or incorrect) it generally makes it obvious which profiles should merged and which need to be re-connected elsewhere. But there needs to be some documentation of those relationships!
Several of the 'curatorium' will mark profiles as a MP even without a lot of information when there are a lot of similar profiles nearby, just in order to "put a stake in the ground" to begin to untangle them -- or to prevent a mis-merge with a "nearby" profile which has the same name but different family relationships (e.g.: mother-daughter, cousins, etc).
While there is no 'rigid standard' for how to document those situations, I personally will put in the Curator Note as "Merge Master" -- by which I really mean that "I'm reasonably sure this is a person in correct relationship to the parents and/or siblings and/or children; please update as documentation is added." It also means (to me) that any other curator can 'take over' that profile if they have new information and wish to update the Curator Note.