Sure, but there are still several instances of characters "sensing to good" in others. If they can do that, why can't they also sense the bad?
In this game, Mirialans have a "sense alignment" social ability at level 1. But Jedi Masters have zero idea you're playing a murdering, slave trading psychopath?
Edit: Familial bond doesn't explain how Vader senses Kenobi in the first film. Given the similarity in dialogue, I assume this is related to force powers or alignment in both instances, and not blood.
Other examples: Luke not sensing his own sister and Kenobi's sensing the destruction of Alderaan from light years away.